In terms of 2D quality, just about every decent card on the market today will give you great quality. If you are buying for 2D and 3D, I suggest you buy the Velocity 4400. Because it's all on one card, the quality will be maintained. Even if the Matrox has slightly better quality, it will end up worse because you'll need to use a pass-through cable to the 3D card. Buying a single TNT card is also usually cheaper than buying a separate 2D and 3D card.
Personally I like Matrox a lot, but the reason they brag so much about the 2d capabilities, is because they are getting beat down by the newer cards' 3d . I do 3d animation ,graphic design,and some cad work., alot of 2d. And I seriously doubt some 24-7 quake fragger really cares if a cards 2d can push a refresh rate 10Mhz higher than another.
don't forget, the refresh rate is also limited by the monitor. From the 2D refresh rates of the TNT, I think that most people will be limited to what their monitor can do rather than the card's limits. There ain't no point in one card being able to go 10MHz faster if you can't actually use that last 10MHz!!