Thanks guys but here is the situation...
The resale value of the cards are an issue, and so is performance. Now, my 320MB plays all quite fine for right now (except Crysis, that I have to play medium-high, but that is expected).
I just bought a 19" widescreen monitor (1440x900) as a temporary escape measure from my 17" CRT. I have tested this resolution on one already so I know that my rig will hold up, no problem. This is, this is a temporary upgrade. The aim is a 1920x1200 resolution (24" - 28") so therefore, more video card will be needed eventually (hopefully sooner than later).
As for CPU power, a quad core is definitely on the cards, but not quite yet. Order of priority for me right now is: Monitor > Video Card > CPU.
So eventually I should be okay but it is just that I have to be taking it step by step. I really like the Samsung 2493HM, BenQ G2400W, Gateway FHD2400 and the Hanns-G 28". Still somewhat undecided there.
Video card now...9600GT or 8800GT.
Video card later...GT200 (what will be the different variants by the way??).
CPU...no problem deciding here....Core 2 Quad Q9450.
Thanks for the input guys. Keep it coming.