I'm almost ready to buy myself an iMac (I'm finally converting over from a PC) and I was planning on upgrading the RAM to 8GB. A friend of mine at work has suggested that I just get 4GB and upgrade it myself later on. Is this a good idea? It's only $200 to upgrade the RAM directly from Apple (or cheaper with my wife's work discount), so is it worth trying to save a few bucks or am I just asking for trouble down the road with compatibility problems or something like that. How many memory slots does the iMac come with? I'm also worried that if I get 4GB and it will be two 2GB cards taking up the two slots so I'd end up having to purchase two 4GB cards or an 8GB.