Hello there, um... why would you want to install Windows 7 on an iMac without using Boot Camp? i mean, is not that it won't run OK, but if you have an iMac it's because you actually USE the Mac OS X
i don't see the point of having a +1000$ Apple Computer and not having its OS.
It'll run just fine, but personally, i'd install it with Boot Camp to have dual boot (Mac OS X / Windows 7), it wouldn't hurt your feelings or pocket or nothing.. and you'd still have the best of both worlds
My .02 cents!