Ok, so I play my guitar with a lot of effects, so a good clean channel is a must for me. However, I also need the same amp to be able to get real dirty for when I play my solos. My musical styles encompass post rock, sludge, doom, and power metal. I am thinking of the Carvin V3, but can anyone suggest a better option?
take a look at Mesa Mark series amps or maybe even a Roadster if you can find one. These will be used at your price range.

I've had a chance to play the carvin a few times, and it wasn't really suited to my personal needs. It can get dirty, but i have always been left wanting more from it. It didnt really hit the distortion sounds i wanted.

you may also want to consider getting two amps. possibly one like a fender for your clean sounds, and one such as a peavey 6505, Mesa Rectifier, ENGL, etc for your distorted sounds, then control it with an AB switch.