Buy as little memory as possible, then replace it with something from here:
http://www.newegg.com/Product/Produc...e=4GB+(2+x+2GB)
4GB of DDR2 200pin SODIMM average around $80, and it's a snap to install. Sometimes Dell charges outrageous fees to go from 2GB to 4GB, so anything more than ~$100 means you should just go get your own. The warranty remains solid if you replace RAM; of course, if the RAM itself turns out to be problematic, the Warranty for the RAM would cover that---Dell still covers the rest of the machine, though, no problem.
I don't believe this BIOS/Chipset will run memory at anything other than 667Mhz, regardless of what speed is advertised...? Someone should confirm this, though, cause I don't know for sure; I'm sure Dell would have sold the things with 800Mhz RAM if it were possible, simply because it's so freaking cheap (see above)!
These computers are incredible...definitely go buy one! If you DO end up waiting for the x9000, please run some benchmarks and start a thread about it when it arrives, since no one seems exactly sure what the difference will be in terms of gaming framerate/overclocking ability/etc. etc.
mark
PS. CRYSIS absolutely shines on these machines, especially with the CPU cranked to 3.4Ghz...you can't hear the fans AT ALL, either (at least, not over the gunfire and explosions, lol)! Whoa, boy, does it get HOT, though, heh...the keyboard and palmrest aren't any warmer than normal, thank goodness...just the rear underside part that touches the lapboard I use...also, you could literally fry a bloody egg on that monstrous powerbrick...seriously, you can't TOUCH it without wincing!! Gotta hold it by the cords to pack up, heh. Totally worth it, though, when you're stuck overnight alone in a hotel room for the 14th time in a month.
PPS. This one claims to have CAS Latency of 4 (as opposed to every other DIMM on that page)...can anyone comment on this particular company/RAM/legitimacy of CAS4? Does one CAS stepping make any real difference this high up already?
http://www.newegg.com/Product/Produc...82E16820231154