Paul's wife got him a new iMac for his birthday and he's worried because he keeps hearing an update is "imminent." Leo says so what? The rumor sites are making up dates and pushing the meme that updates will happen any minute. The truth is, it could happen tomorrow, or it could happen next year. So we don't really know.
Paul is wondering if he should return it and get store credit. Leo says that Apple is in no hurry to update the desktop line. As far as retina displays go, a 27" retina display would be way too expensive and has too many pixels for a computer to drive them. So a retina iMac isn't going to happen any time soon. It would have an IvyBridge processor and updated graphics processor, but the performance boost will really not be all that great for anyone but gamers playing high end 3D games. Also, Firewire will no longer be supported, and will be replaced by USB 3.0.
If Apple releases a new iMac within 30 days, he'll be able to return it for that one if he wants. So Leo advises keeping it. In fact, if Apple releases an updated iMac, it probably won't be until January.