I'm going to get a 27" iMac this weekend and I'm trying to decide if I should go with a quad core. I know I don't really need it now, but I'm going to have this computer for at least 3 years. However, I don't want to have to make any major hardware upgrades during these 3 years (Will apple even make upgrades for me? Does it void Apple Care if I do it myself?). I'm a freelance web designer and developer, so a lot of my time on my iMac will be spent in gimp/photoshop, text editors, possibly dreamweaver, and a few different web browsers. My main browser will probably be Firefox. What do you recommend for me?