Honestly, unless you are spoiled at playing every game at 4AA/8AF, then your Radeon 9800Pro will become obsolete in 6 months when (if on time) Half Life 2 and Doom 3 come out. There are some games where the 9800 Pro begins to struggle today with high quality settings. Of course, you could always revert to using 1600x1200 and no quality settings on. Believe me, at that resolution half of the jaggies everyone complains about disappear anyways. In that respect, your card will easily last you another 2 years. The basic argument is that either a) your card has features which current/future games take advantage of like prettier pixel shaders and effects, etc. b) it's so fast you can play any game with high quality settings. In your case your card supports Pixel Shaders 2.0 I believe, and the games on 3.0 won't come out for a year. I remember getting my Radeon 8500, it took 1 year for a decent 8.1 game to come out after I bought it. And to this day I can play any game (aside Far Cry for some reason?), at least at 1024x768. Need for Speed Underground at 1280x1024, so is Unreal 2, Unreal Tournament 2003 at 1600x1200, Call of Duty at 1280x1024, and with some i can use AA or AF. And my card is like 3 years old now? I just dont understand the use of running a game at 300FSP, or vs. running it at 50-60, except for bragging rights. Now my card doenst have the latest direct x 9 featurs so i will miss some of the eyecandy anyways, but yours wont for a while so you have that side covered. If you can live without having to turn on AA and AF at every point and resolution and compromise, then you have nothing to worry about. Just read this
article, and you'll will know that for future direct x 9 games, everyone who bought nvidia fx cards should be crying right now. If you are a person who doesnt like to compromise, then of course you'll always need a top of the line card to play at the highest resolution + best quality image possible. And a less expensive version of 420 won't come out for another several months, I believe September is when the mainstream versions will arrive. That's a long time to wait.