Hello,
I don't want to hijack the thread but I have been wondering this too; I currently have a Mac Mini and I am going to buy a MacBook in the next few months. I don't do anything heavy on the Mini but I am constantly using more than 1Gb RAM, so I had convinced myself I should get at least 2Gb on the MacBook. If nothing else, I will probably want iTunes open whatever I am doing on the MacBook, and we all know what a memory hog iTunes is. I never seem to run out of memory with 2Gb on the Mini, so surely its worth the extra? (£60 here in the UK). If I am wrong, please tell me otherwise as the missus can always help spend the money elsewhere than on technology ;-)