My new iMac just arrived and I can't wait to open the box. I do, however, have a question. If new iMacs come out this Tuesday (which seems to be the rumor), will I be able to return the iMac that just arrived for one of the new machines? I custom built mine so I imagine I'd have to send it back to Apple vs. taking it to an Apple Store. I think I read somewhere that someone had bought a macbook a few days before Apple released a newer version (believe it was just processor and HD upgrades) and they were able to get the latest version without any extra charges. Can this happen? Also, what could the upgrades be to the new iMacs? Are we talking major differences vs. the current version or just a bump to Penryn, etc.?