A few months ago I bought a MacBook Core 2 Duo with 512MB memory. I think that the Intel switch is beginning to settle down and it looks the initial teething problems have been resolved more or less (although Microsoft Office and Photoshop are still not available as native Intel binaries).
However I was seeing the spinning disc of death just a bit too much so I decided to upgrade the memory to 1 GB. The MacBook has two memory slots but unfortunately for performance the Duo processor likes evenly matched banks so my MacBook shipped with 2 x 256MB so to upgrade I needed to buy 2 x 512 MB chips.
Installing the memory seemed straight forward however in the process of upgrading the memory I somehow messed up the power so the battery wasn’t charging. However I reset the system management controller and that seemed to fixed it.
The new memory has absolutely transformed the computer and certainly as far as I’m concerned 1 GB is really the minimum memory required for a MacBook.