I currently have 1GB (512x2) and I want to upgrade. I was going to get a 2GB kit from crucial for 101$, but then i realized that it would void my applecare. ( i know i can just keep my orginal sticks and put them in if something happens, but i dont want to take the rist). Anyway i decided to just get a 2GB stick for now and just leave one 512MB in unitl apple care runs out then just buy a 1GB stick. www.datamem.com has a 2GB stick for 165$, crucial has a 2GB stick for 308$. I hear good things about both companies, but the price is so different. What should I do?