I'm having a hard time dealing enough damage with bows. Even when sneaking, and using poison bandits, zombies etc. still have around 50 % of their hp remaining. Is bow just not as good as swords?

And how is bow damage calculated - is it the damage of the bow and the arrow combined, or the average of the two?

I really want to play a bosmer assassin who relies on bows, and daggers as backup, but having a hard time getting it to work. I usually build him up something like : Thief - Speed and Agility - Stealth - Sneak, Marksman, Blade, Conjuration, Light Armor, Acrobatics, Armorer.

Bows can deal more damage per strike than any other weapon in the game (not including magic).

It's just a matter of increasing skill and agility. Skill is more important.

Total damage is the arrow damage plus the bow damage.

The main problem with bows as a weapon is that it takes longer to set up a strike than a blade, blunt or H2H. The key is to keep distance. Preferably hidden. Also poisons help a lot and work well with bows. Also Acrobatics goes well with marksman character, particularly if you can jump on some relatively inaccessible place - like a big rock or ledge - then shoot down at your enemies.

My current character uses a bow as the primary weapon and it is more than viable I think.

What level are you? What is your Marksman skill?
Bow damage is :
1. the Damage from the bow
2. the Damage from the arrow
3. the damage from the bow enchantments
4. the damage from the poison
5. the damage from the sneak modifier
So you have a bow that does 25 damage. Say you have Fire Damage 25 points on it.

If you are sneaking, that's (with the 3x sneak bonus) 75 Damage with the Bow + 75 Damage with Fire + Whatever kind of poison + the arrow, which varies greatly, I'm currently dealing 17 Damage with an unenchanted Perfect Amber Arrow, for another 51 damage for just the arrow....

At 100 in Sneak, when I attack someone undetected, the game rolls for the fact that my bow shot will IGNORE any armor that the enemy is wearing, that is, their armor doesn't take away points from my total bow damage.
I could only start scoring one-hit kills with the bow, around level 75ish in Marksman. All that time of course, I worked on my Alchemy skill, so I could deal the most damage with poisons as well.
I use the bow exclusively until I am overwhelmed, then switching to destruction magic and illusion if I need to high-tail it outta there. Just keep pumping arrows into your enemy, falling back if need be.

A bow backed up by a dagger works fine. One challenge to watch out for is the cycle of using the bow to piss off your foe, then breaking out your dagger to continue the fight. That leads to slow leveling of your bow which just makes the problem worse as you find yourself relying more and more on your blade. You want to optimize your bow with good agility and marksman skill, good poisons, sneak bonus. You want to keep your distance of course, and detect life is very helpful for this. And of course you need a patient, methodical and sneaky play style.

My character does not back up her bow with melee. A bow is the only weapon she will touch. She backs it up with a little magic. Rather than breaking out a dagger (which she won't touch), she uses illusion to immobilize any charging foe so she can continue shooting her bow. Illusion can similarly cause crowds to thin their own ranks while she watches from hidden safety waiting to snipe any survivors. Or she will shoot to poison her foe, then demoralize him so he runs away to die instead of charging her. She uses absorb health on touch for underwater combat where her bow doesn't work very well. Her only interest in destruction magic is drain speed and weakness to poison to support her bow killing.

well last night i just got my marksman to 50, so i can zoom in which is fun, Ruby has good acrobatics to help her take vantage pointsm and she uses paralyze poisons (2 seconds) if the first strike doesnt kill then they are paralysed so they take another shot, almost certainley dead. works well, my agility is high-sh, around 70 i think.

i use madness bow, and i'm level 8 on middle difficulty

The most annoying part of being a Marksman is deciding how soon you want to get to level 50 and gain the ability to zoom in on a target. It does take more planning and strategy to play a stealth character, but most people will play Marksman based characters to the higher levels and not abandon them at level 25 because they are boring to play/overpowered.

I cap my archer at level 20 by picking a few major skills to never use. She is full power by then and we see no real need in letting her foes just keep building up into hitpoint pools. We don't care about leveled loot and everything we want in the game is available by level 20. Some folks might prefer to cap at level 30 because beyond that, there really is nothing new in the game except the same foes with more and more hitpoints. Buffy reached level 20 at 400 hours; she is now still level 20 at 600 hours and loving life in Tamriel. :dance:

When I saw the opening post, I thought "how often has my Claymore-wielding character killed anything with one blow?" And why would anyone think an Archer gets that privilege?

The problem you're having is more one of "what do I do when I've annoyed them with my first shot?", so the answer is going to be learning tactics for the rest of the encounter. As Acadian has pointed out, one option is using poisons etc. to stop them from attacking you immediately, by slowing them, demoralizing them or whatever suits your style. Another is to make the arrow the coup de grace after they're weakened by another offensive method, such as summoned allies, spells or whatever. Casting a "weakness to whatever's on my next arrow" spell helps, too.

The Marksman's greatest advantage is that they get the first shot if they're careful, and thus can dictate what happens. Use the terrain to advantage, and know your enemy.

Also remember that undead are immune to poison, and I think argonians are too. Redguards also have a 75% poison resistance FYI.

If you are on PC I would recommend this mod: http://tesnexus.com/downloads/file.php?id=23484

It makes your arrows fly at a faster, more realistic speed, and they also fly flatter. It isn't overly unbalancing, and very helpful. I would highly recommend it.

The well-studied mystic archer learns how to defeat poison immunity, even while retaining her stealth bonus. Buffy details her thinking and experience in this snip from Episode 55 of her Journal:

* * *
One ancient sanctified dead remained. A change in tactics - rather an experiment - was in order.

I poisoned an arrow, slipped it into my boot sheath and made ready a new, untested spell. After a quick mental rehearsal, I snuck toward a firing position that would afford a clear shot. The ghostly creature had its back to me. Calling forth the complex powers of destruction, a glow formed in my right hand. The moment the spell left my fingertips, I quickly nocked and released my poisoned arrow. Boderi, my University advisor, called it 'chasing my spell' and had relentlessly made me practice the tactic. The spirit - normally immune to poison - turned green as the vile liquid from my arrow made its presence known.

Undetected and fascinated, I crept closer. After a few more moments, the spirit collapsed, claimed by my poison.

It worked!

My spell had two components. First, it temporarily but dramatically weakened my enemies to poison - in this case even countering the immunity of these undead. The second aspect of the spell was that it totally but briefly drained a victim's speed; this rendered the target unable to remember being hit by a spell and allowed me to remain undetected while 'chasing my spell' with an arrow. In fact, the drain speed effect was similar to one of Slayer's enchantments - and just as effective at preserving my stealth after striking.

The spell was quite demanding to cast, but I was confident that as my magical skills increased, and with practice, I would better be able to manage it. In fact, I hoped to eventually add a long soul trap effect to the next version of the spell.

Visions of green ghosts, zombies and atronachs danced in my head!

Careful not to slip on the ghost puddles, I collected the useful remains from my prey.

* From Buffy's scrapbook: http://i668.photobucket.com/albums/vv43/Acadian6/Buffy%20I/ScreenShot94.jpg