What's the most powerful non-spellcasting class through 10th level?

[Edena_of_Neith]

In my (uneducated) opinion, the straight rogue.
Most of the characters I've ever run, would not want to run into a hostile, 10th level Lidda. They would never even know what hit them.

 

[Caliban]

Base classes only, or are you considering prestige classes?

Dwarven Ftr4/Mnk2/Exotic weapon master 1/Pious Templar 1/Dwarven defenter 2 has a powerful mix of defensive abilities (not offensively powerful, hard to kill via magic).

Brb1/Fighter4/Dervish 5 (with falchion, dodge, mobility, combat expertise, elusive target, power attack, and whirlwind attack feats) has awesome mobility, and can take an attack at his highest bonus against everyone he can reach in a single move.

Scout7/Dervish 3 - a two sickle wielding version of the above dervish, without the whirlwind attack feat.

 

[Bryan898]

Vampire Fighter 6/ Blackguard 2. Give him the feats Karmic Strike and Elusive Target from CW, as well as a big two-handed weapon or natural attacks for energy drain. His DR will let him constantly soak attacks and retaliate with Karmic Strike without much hit point loss, meaning he'll way outdamage the PCs. If you choose energy drain he'll be getting 5 hp per hit, practically negating all hit point loss from physical attacks.

Use your Dodge bonus and Elusive Target against the warrior types. Unless they have silver magic weapons they'll likely have a hard time doing much damage without power attack. Then for every 4 or 5 damage they do, hit back with karmic strike for 15-20. The diverting defense ability will be especially irritating when the fighter's swings start hitting the party's rogue instead.

Rogues are almost a non-issue here, between being undead and how high an AC a fully armored vampire can easily pull off.

Dark Blessing and a +4 Cha bonus will help with any saving throws needed against any spellcasters. Add in all the immunities for undead and resistances for being a vampire and he should be fairly well set to cut through the spellcasters with ease. If you're worried about turning, set the fight in an unhallowed or desecrated area.