O0oDC :
i have a choice between the geforce 9800 gt 1gb and the 9800 gtx+ 512mb. price shouldn't effect the decision.
Most likely the 9800gtx+
The 1GB of memory on the 9800 GT won't come into play until very large resolutions, but the 9800 GT itself isn't strong enough to run those resolutions effectively.
If, for some reason, you're running 2560x1600 (or maybe even 1920x1200) and those two cards are your only choices, then get the 9800 GT 1GB