For those of you lucky enough to be picking up a new iMac, you may want to bump up the memory a little bit from Apple's standard configurations. Apple is notoriously pricey (though less so recently) when it comes to memory upgrades so you may want to consider a doing it yourself. No worries. Apple has you covered there too.
Apple's new support document HT3918 covers the easy steps to upgrading your RAM (spoiler - it is exactly how you'd think you'd do it). Apple requires the same 1066MHz SDRAM that were in previous models. You can pick this up at