I'm trying to decide between iMac and new MacBook pro (not retina though).
Persuade me.
It really depends on what you're looking for... I'm a current Apple advocate, but consider myself about as objective as you can get. I used to be a major MS zealot and slammed Apple for years before finally switching... Honestly, the only thing that did it for me was the introduction of bootcamp and the knowledge that I could run both a Windows partition along with my MacOS partition. I still have a Windows partition...
I used to have a Macbook pro but ditched it for a 27" iMac. I tried using an iPad 1 and then 2 as my mobile computing devices and wanted to use the iMac as a primary desktop. I had previously been using the Macbook pro and an external display as my primary computing station. If you're not going to be terrible mobile or need your computer in many places and can get by with say... an iPad for basic needs such as web surfing, email, reading, etc... then iMac can give you more computing power at a cheaper price and is an elegant computer. However... I'm more of a power user and now that I'm traveling quite a bit, moonlighting, visiting family, etc.. I really miss the mobility of my previous laptop, so that's primarily why I'm going back to laptop although I'll miss the iMac.
It just depends on what you need. If you don't have computer mobility as a primary requirement, then iMac is the way to go. Awesome computer. If you use Windows applications, get a copy of Windows 7 or 8 and install it on a partition and use Parallels or boot straight into Windows for maximum flexibility.
I used to think the Windows platform was superior, and even a superior development platform but I have since changed for various reasons but honestly... I'm not a diehard fanboy and if Windows came out with a superior OS, I'd easily be swayed back, but after using both operating systems extensively for both programming and productivity, I can honestly say that I truly consider, somewhat subjectively of course, that the MacOS is the superior OS for a variety of reasons that I would need pages to expand on. It's an evolutionary leap forward in front of Windows.
I have no complaints about the iMac, just that I miss having a laptop, so that's why I'm switching back. I even tried using a bluetooth keyboard with my iPad while traveling, etc.. but I just can't do everything that I need to do.