What'so frickin special about Mac Memory modules?
Yeah, it's ridiculous, although they've gotten better with the latest Mac Pro. The prices aren't nearly as insane as they used to be, but it's still a big markup.
Trevor: I'd make one correction. All the manufacturers do the same thing on their high-end machines. On the more budget computers (Dell Vostro, for example), you can still double and triple your RAM for reasonable amounts close to market rate. I'm not sure why these companies think that just because it's a high-end machine, people will pay ungodly amounts for RAM.
Cris: I'm happy to hear that you can just get normal Crucial memory. If people are still concerned, they can also go to someplace like macsales.com, which is where I hear a lot of people go to get Mac RAM, and it's only slightly more expensive than the stuff you can find on Newegg.
Still, I'm just glad that I could throw 6GB in the machine I just built for under $100.