I'm about to embark on Dawnguard and am trying to figure out if I should bother bringing silver weapons rather than my personal favorites. What is the Dmg modifier/bonus when using e.g. a Silver bow or axe rathre than a normal weapon? I have a Longbow that I like and it does quite a bit more damage than my Silver Shortbow, but if the bonus from the Silver bow makes the total dmg exceed that of my Longbow I'll probably bring it instead.

What's the damage for crossbows in your modded game? In vanilla, they have different perks and drawbacks compared to normal bows. They draw instantly, have faster projectiles, do more damage than their regular counterparts, can be "enhanced" to have some armor piercing power, and have explosive projectile options. Conversely, they take longer to reload than a bow does to draw, their ammo isn't compatible with regular bows, and there's only two material tiers: Steel and Dwarven.

According to the UESP, silver weapons do an extra +20 to werebeasts and undead. However, they're pretty low-damage to everything else.

The Dawnguard have to specialized melee weapons, an axe and warhammer, that are Dwarven tier in normal damage and do an additional +10 (but just to vampires). The crossbows do no special damage, but do have significantly more normal damage than a comparative bow of the same material tier. Bolts are equal in damage to arrows of the same material tier, and explosive bolts do +10 and +15 damage for steel and dwarven bolts, respectively. They also have a very satisfying *THAK* noise they make when they hit their mark.

If you want to tell the difference between normal and explosive bolts, give one of my mods a try: http://www.nexusmods.com/skyrim/mods/21922/?

I use SkyRe so the dmg is very different from Vanilla. Overall crossbows are just below longbows in dmg (I didn't check at the beginning of the game as I'm now lvl 10 and specializing in longbows) and shortbows are below crossbows. I play an archer type so I don't use crossbows much, just for fun on occasion. But if +20 is the standard bonus against undead then that answers my question and I'll be sticking with a regular longbow. I imagined it was a % bonus rather than a flat figure, though.

I don't really use explosive ammo as I like low-fantasy worlds and want to keep it simple and I don't use magic either. I only use the enchanted weapons I find, I don't enchant them myself.