Those pictures look great, but I wish the monitors had borderless displays. It looks jarring to jump from screen to screen. Nevertheless, progress is progress.
If you ever need help calculating power estimates, there are some good PSU calculators online such as this one:
http://extreme.outervision.com/psucalculatorlite.jsp
Enjoy!
Yes, the 9800GT and HD 4850 are superior to the GT 240. If you need any further clarifications, check out this cool hierarchy chart:
http://www.tomshardware.com/reviews/geforce-310-5970,2491-7.html
As for memory, GDDR3 vs GDDR5 and 512MB vs 1GB don't have much difference except for gaming at...