well by sneaky standards the best character has the 30 x multiplier to dagger backstabs plus x2 from darkbrotherhood gauntlets and a dagger that does 150 damage (don't know how but I've done it before as a smithing master)
that's somewhere around 4800 damage every sneak attack. or you could pull a 300+ bow/crossbow and do 900. less effective, but better at range.
by warrior standards, heavy armor, duel wield or two handed or one hand plus spell. my most recent battlemage like character breached the armor cap with daedric armor, and his sword, Withring, did over 400 damage every slice. not to mention if I could pull of a sneak attack, that's what... x 10? I don't really remember that perk, I only get it to get deadly shot.
by mage standards.. well, all mages rule. XD