I finally built a new rig about 6 months ago [780i, Q9450 & 4GB ram (win xp)] but still have an old Radeon 1900xt which has been running like a champ. Been standing on the sidelines watching the 8800 series, 9800s, GX2's and now the 280's (and even the 4870's) and am wondering which is best for...