There are so many bands, across so many different genres, I couldn't even begin to start picking out the ones I like more than the others. I can just pick out the ones that I think have/had the greatest potential or unique sound, but that doesn't necessarily mean they're my favorite. I don't typically get hung up on a particular band and such. I just let the music flow through me, if you'll excuse the lame new age analogy. I go through periods of time where I'll look into a particular type of music for a while, and try to expand the number of artists I listen to in that category (right now I'm really wanting to start listening to Hüsker Dü and Agent Orange-type bands; age doesn't matter). Of course, if I had to pick just two, you'd probably find them in the Industrial section. If I had to choose just two whose music left a lasting impression, I'd probably have to say Stabbing Westward and Skinny Puppy.
Stabbing Westward's guitar work is so sharp and clean, despite the fact they play Industrial Metal (which tends to amp up the distortion), that it's almost like a knife cutting into you. The only other band I've found that's that crisp is KMFDM. Taking a listen to the song "Torn Apart" from their Darkest Days CD is just amazing. On top of that, the lyrics are incredibly powerful. Dark, moody, introspective, metaphoric, at times bittersweet, and in the case of the song "Sleep", emotionally crippling in it's depiction of a victim of sexual abuse (like "Janie's Got A Gun" without the 'happy' ending).
Skinny Puppy, on the other hand, makes an excellent case for dissonance. The samples, loops, and sound clips interjected relentlessly throughout their music really gives your brain a workout. It's definitely an aquired taste, depending on just which song you choose to listen to-some are melodic and ambient, like "Worlock" or "Assimilate" (or, off their newest album, "I'mmortal" or "Empte"), where others are pure chaos, such as "Convulsion" or "Who's Laughing Now?". Even in the midst of that noise, you can hear orchestration, like a train running off its tracks but yet still managing to stay upright by some unknown force.