Re: gee, skill.
I have mine set at 2.2V @ 4-4-4-12 DDR2-800. I'm sure you could push it well past that if you wanted but I wouldn't recommend using more than 2.3v. Also, if you're using a C2D processor, C2D processors don't really benefit from low latencies so you could easily get a good clock with CAS 5 or 6 with 2.2/3 volts. I'd suggest you look into that if that's the case with you.
Antec NeoPower 650W
Intel Core 2 Duo E8400 (w/ Arctic Freezer 7)
4GB DDR2-1000 G.Skill
Sapphire x1950 Pro 512mb (w/ V700)
250GB, 500GB and 1.5TB Seagate Barracudas (2.25TB total)
Fatal1ty XtremeGamer sound card *** generic TV tuner
Xclio 3060 case *** HannsG 22" monitor
XP Pro / Ubuntu 7.10 *** Razer Copperhead and Tarantula