Nvidia is the trend, yeah, they've been since the voodoo days ended.
However I've been a happy ATI user since I migrated from my old GeForce2.
filtering was fixed a looooong time ago and most of the shader issues were due from developers only testing in Nvidia. Same happens if you do it the other way around.
If price is not an issue, go high-end Nvidia+Intel.... if it is, go mid-range ATI+AMD, which packs more punch than its counterparts at the same price range.