Just so everyone knows, I purchased the mid 2011 iMac with Lion preinstalled & a 250GB SSD and upgraded the RAM to 32GB from OWC. It ran like sh#t and I had nothing but problems, even after a couple of fresh reinstalls which took literally days to set up. I downgraded it to Snow Leopard and it's the fastest computer I've ever owned and I do ALOT of video editing and graphics work. If you don't have a way to run Snow Leopard, don't expect a whole lot from the 32GB of RAM in the new iMac's. It's not the computers fault, it's going to be the OS. Lion/Mountain Lion are bloated turd OS's.
That said, after today's keynote, I don't regret my purchase of the mid 2011 system literally AT ALL. In fact given the chance to do it all over again, I'd take the previous generation iMac over what I saw today. Apple has lost me as a customer on future hardware purchases. I can not understand their, almost psychotic, obsessive urge to make everything thinner. I have not been impressed by anything they've announced this entire year and they've refreshed everything they've got except the Mac Pro.
I've said it before and I'll reiterate it here, Apple may be selling phones, tablets and computers now in 2012, but in about a couple of more keynotes, with all of their products being soo expensive, unsubstantial in size and disposable, people are going to realize that a little heft in a device and upgradeability is not a bad thing, especially if it prolongs the devices lifecycle. I still have my pre-unibody 2008 MacBook Pro with a user replaceable battery and I'd take that any day over the new disposable computers. It still runs Snow Leopard and I've maxed out the RAM in it. If I ever want a faster laptop, I'll upgrade it's hard drive to an SSD. And if my iMac ever fails and can't be repaired, I'll be building a hackintosh which can run Snow Leopard since none of their current lineup is backwards compatible. Future Apple software is dead to me unless by some miracle they pull their heads out and are able to turn their current direction around.
It's like Cook and Co. have set their sites on failure and can't see anything until the numbers start to drop. Which of course, they will, maybe not soon...definitely not this year, but they will and when they do, there will be a mass migration the size of which you haven't seen since Apple released the iPhone and Jobs will not be back to save them.
Just my thoughts. Take it or leave it.