2D visual quality is extremely dependent upon the individual manufacturer, and some nVidia board manufacturers have a tendency of using rather poor filters which has resulted in nVidia getting somewhat poor reputation in the industry as references 2D visual quality.
VisionTek and Gainward usually have pretty good 2D though, slightly below ATi's standards IMHO but not by a great degree. LeadTek is slightly further behind still but quite good.
Beyond those manufacturers 2D can range from average to to very poor.
As long as your running 1152x864 I wouldnt worry too much about 2D visual quality, as most cards providea decent image at such resolutions, but if your hitting 1280x1024, or 1600x1200 or possibly even higher then I'd definitely start paying close attention to which manufacturer produces your board.
Unsurprisingly, neither ATi nor nVidia tend to match up to Matrox in terms of 2D visual quality... but then Matrox has long been the king of 2D.
A lot depends upon what monitor your using, and your eyes as well. Some people's eyes just seem naturally more attuned to variances in 2D output quality whereas others are tend to be perfectly happy with relatively low quality 2D output even at the higher resolutions.
In terms of DVD playback, ATi has been the king of DVD playback for quite a long time now and are constantly improving DVD playback slightly with each generation of cards.
nVidia provides pretty good DVD though, and besides ATi they provide the best DVD playback of any of the mainstream graphics card manufacturers IMHO.