Looks good, but a couple suggestions...
You might consider getting a faster dual core instead of a quad core. Unless you use specialized applications that will take advantage of the quad core environment, you're going to see better performance with a faster dual core.
Liquid cooling tends to be more problematic than helpful, and requires a bit of maintenance. There's always the chance of leaks, and they can be a pain to assemble/disassemble if you ever decide to swap parts out. The new Intel processors actually run quite cool with fans (much, MUCH cooler than my old AMD), so if you're not planning on overclocking and want fewer problems, don't spend your money.
Windows XP (32 bit anyway) is not going to recognize all four gigs of ram. Unless you plan on using vista, 4GB is going to be overkill anyway.. might want to invest in 2 or 3GB of faster ram.
You might consider two hard drives.. a faster but smaller drive for your system drive, and a larger drive for your storage drive. This does make a difference.
Stick with one video card.. go better if you can (might even want to check into the 9XXX series that are coming out.. they are getting very good reviews). The little bit of increased performance on an SLI setup is about the worst "bang-for-the-buck" you can do right now.
Now keep in mind that's a pretty monstrous system you're looking into, and will perform very well, but you can easily save a few a bunch of money and get something easily 90% as fast.. unless of course, you have money to burn.. or you just want something you can show off!
Enjoy!
