I guess this depends on whether your buying a new one or an old one. 1GB of memory is the minimum I'd get, if your running Mac OS Leopard. And, if you don't store videos, pictures, music, or many programs on your computer, you wouldn't need more than 40GBs of disk space. This however, is only theoretical. The new Macs all come with a minimum of 2GBs of memory and 160GBs hard disk. And, if I were buying an old machine, I'd get a minimum of 80GB Hard Drive, so that if I wanted to put a little digital media on the computer, I could.