I won't speak for mfenn, but since he and I are often in a similar boat on the GPU point I'll give my perspective.
Nvidia and ATI/AMD take turns owning the price/performance crown. I owned a Radeon 9800 Pro (ATI) back when it was the card to beat, and then subsequently bought an 8800GT (Nvidia), GTX460 (Nvidia) and HD7950 (AMD).
Anyone who tells you that either brand is across the board better or has a history of driver problems doesn't know enough about graphics card or is too heavily biased to be giving advice. They BOTH have a history of driver problems, but they both also generally put out solid, reliable drivers and make an honest effort to fix any big bugs that come up.
Right now if you have the budget for a $250-300 graphics card AMD probably offers the best value in that range, but that hasn't always been the case and won't always be the case. Every generation of cards is different, and you can never count out the possibility of a steep sale on one card or another, although it's rare in the GPU arena that a sale is big enough to swing the price/performance pendulum from one manufacturer to the other.