I've always been an Nvidia fan. But I've had 3 of them break on me. I even fixed my one card with a multimeter and a soldering iron back in '05. Still works to this day. My current 8600GT is throwing odd lines across my screen as well and I'm pretty sure it's going to conk out any day now.
Unfortunately for the medium level cards, ATi seems to be better, whereas NVidia still dominates top end cards.
So it'll either be the 4870 or 4890 if I had to choose a card.

