Note to everyone who’re updating the RAM in their Mac mini’s: It’s 667Mhz PC2-5300 DDRII SD-RAM SO-DIMM. I just made the mistake of forgetting the SO-DIMM part and I now have to return a pair of oversized RAM sticks… Good thing it’s not complicated. Now I know why Apple can get away with charging excessive amounts of money for renamed Kingston RAM; people like me just can’t be bothered.
Update: I’m happy to find out it’s not just me being stupid. The MacWorld editor-in-chief made the exact same error, as chronicled in this podcast

I know your pain.
I recently bought an Airport Extreme card to put in my Quad G5 only to find that newish G5’s dont use Airport Extreme cards. In fact, they use a combined Airport/Bluetooth card that us mere mortals cant buy, and shouldn’t be installing.
Incidentally, if anybody feels like bying a cheap never-used-just-unwrapped Airport Expres card. Let me know. (PS: Its located in Denmark)
Personally I find crucial to be the best source of RAM, they have a neat little expert system to decide what kind you need (no mixing dimms with sodimms etc…)
Nothing wrong with alot of RAM in my opinon!