I have a 15' monitor with a maximum resolution of 1024x768. so which would be the best card to run all games for about 4years (with max detail). I think ati radeon hd 5770 would be the best
with a 15' monitor? The 5770 is WAY overkill for that. 4650 may even be overkill...
5770 would be a good choice if you are planning on upgrading your monitor to something in the 20-24" widescreen variety. Otherwise, it's way more than you'd need. You could probably do a 5570 or something like that and be ok.