Current iteration is mid-cycle, check the Buyer's Guide tab at the top of this page. Since it seems that they've gotten their footing with it again (fixing the screen issues as well as shipping problems) you could get the iMac now and get the iPad when it comes out, have a bit of space between those purchases.
I'm aware of the buyer's guide. I thought I had heard a rumor on some site about updated iMacs in March. Doubt I'll buy now anyway. Need some time to think about it and sell off my old equipment. I'd prefer 27", but don't think my desk is big enough. My 26" monitor right now takes up way too much space, which is why I'd like something a little smaller. Yes, smaller! Or maybe a bigger desk. I might as well wait the 3 months or so until they are refreshed and hope for cheaper quad-core models.
Another deal breaker is the line-in video. The 22" model doesn't have it while the 27" does. I play xBox Live in the study at my desk (so I don't annoy the wife) and I'd need to be able to hook it up using one of those new display port adapters. HDMI would be even better, per the rumor from the other day. And yes, it is possible to game on IPS. Some of the new panels are a bit faster--not sure about the iMac, but mine is fine.