I am also in the market for an iMac in which I can be able to purchase one as early as next week. The only thing that's keeping me from buying it next week is the knowledge that Apple releases the new line of iMac around this time of year. I am a web graphic designer and work with HTML. What concerns me the most of the much rumored retina display is that text might appear smaller. I can't imagine working with text on a high-resolution retina display all day long.
As far as what I would like to see in new standard iMac is a minimum of a 2TB hdd(7200rpm), 2.7Ghz i7 CPU, 8gb of 1600Mhz ddr3 RAM( i have gut feeling they'll stick with 4GB minimum), additional USB 3.0 ports replacing the super drive and anti-reflective glass.
I really hope that the June launch is just rumor and they launch in May. I can't wait any longer