You should save a little and get the 2012 late 27" imac the 70% less glare on the screen makes a worlds difference
You're starting to see this option. Hang tight and constantly check the refurb section at apple.com and if you've got a local best buy. Open box are just fine to pick up from BB. I've got a pair of 2011 21.5" and two 2010 21.5" iMacs. We use them for our events as our primary sound sources. They also do DMX lighting control. I've only ever needed the base models with the 1tb storage option (for the audio library). I've been using a 2010 Mac Pro for our home studio and stationary machine. We sold it this past fall when I bought an rMBP. We are now considering, like you, a 27" iMac for the home office/studio. The gains between the 2010/11 models and the 2012 aren't just the anti glare (which IS a biggie!), but USB 3 is huge! Thunderbolt (2011 has TB) x2 on the 27" models and a significantly better GPU. Also, if in the refurb @ apple.com you're able to come across the fusion drive option, you'll love happily ever after
. Pretty cool to have the benefits of the SSD with the capacity of the HDD. The refurb 27" might be a bit more than you have now +/-$1500, but well worth it. If you don't need it now, give yourself 4-6 weeks. The refurb store should start gaining inventory as the iMacs are finally starting to ship en masse. I just did a CTO order through my local Apple store (business store) for a 27"/768ssd/680 GPU. They're expecting delivery by 4/3. I ordered it yesterday. A month ago, this was a 4-6 week wait. They're now shipping inside of 7-10 days. Faster shipping means more iMacs going out...in return means more coming back (for refurb sale). Also, MacMall, B&H and Best Buy are all excellent resellers and sometimes you'll save $100-$150 off Apple retail. You can also save 30-50% off Applecare (I buy AC @ B&H).
Good luck. Have patience. Save a bit more and of you want the 27", buy it. Don't settle for the smaller display. The 27" Apple panel itself is a near $1,000 option if you were to buy a separate display with its attributes.
J