I find I'm presented with numerous factions to join, I just don't want to go down some rabbithole and join something that I'll regret later. Like I know The Companions eventually leads you to

and I'm not too keen on doing that for a number of reasons, but I'd still like the benefits of being a member.

So I'm curious, in your view, if you were a thief/assassin who's sole weapon is bow, which of the various factions would you join and why? Which benefits compel you to do so?

Thanks in advance.

EDIT: Also I'm keen on getting Alchemy/Smithing/Enchanting to 100 as well.

If your character views himself as a assassin then the dark brotherhood is probably a good fit for him. Its hard for me to play evil characters, so ive never done the questline, but one of the cool things about Skyrim over previous games is that once you round out the questline you get a infinite number of stock assassination victims, meaning that you will never run out of work. I have played the Thieves Guild, and you can also get a steady stream of thieving jobs when you round out that questline.

There's all sorts of good loot from the thieves guild questline, but I really like the leather armour you get when you join the guild. It has a nice look to it, and for RP purposes its looks rather light and flexible while still managing to be protective. Guards will comment on the armour marking you as a thief, although nothing really happens because of it. You could work it into your RP to wear a set of hunters clothes like some fur armour to blend in with your bow while your approaching a target. Switching into the more flexible thieves guild armour when you're at the site of the job and then stashing the previous set somewhere safe, only to pick it up once you leave.

You answer your own question. A thief/assassin has no place in the Companions. Kodlak even makes a comment when you firt meet him (if you explore dialogue), that he dislikes "ragged cutthroarts" or something like that....

Embrace your thief, escape Helgen, and make straight for the Theives Guild/DB.... you could easily fall into the vampiric side of Dawnguard later on if you have that DLC

You can join the Companions just long enough to get inducted into them, then drop the questline. You still get the perks of being able to buy Skyforge steel weapons & Wolf armor. "Dustman's Cairn" is an epic crawl, & you wouldn't want to miss it.

Yep, pretty much, but why would anyone want to be a vampire/werewolf? I don't get it, I mean I've seen the limited benefits they give... it seems this dynamic was thrown in as a result of certain tweenage book/movie series but it doesn't seem to integrate very well either for RPG or this genre in general. I mean the negatives of becoming either a vampire or werewolf seem to outweigh the benefits. Then again I remember playing Ravenloft back in my P&P D&D days, so it's not completely out of the genre. But when I can produce weapons which will outgun anything the barefisted werewolf will have makes becoming a Smith/Enchanter so much more attractive.