Ignatz the Insane

I like the opportunity to use scrolls and potions while actually thinking about positioning, specific spell usage, and tactics. With the exception of the first five levels or so, you can steamroll most encounters on the hardest difficulties, especially on a second play through.

Actually rangers are great. There are a few builds to look at in the build forum to help you with talents and abilities if you wish. Although most seem to agree that the rogue is the weakest character to play they are still completely viable depending on the build and playstyle.