I spent a lot of time poking around that marathonguide site choosing mine, so I hope the reviews are reasonably accurate!

The half in Columbus (October) was great fun, it's a nice flat course, really well organized, and I hear the full marathon course is just as nice. If I didn't want to get mine done in the spring, I'd be doing the Columbus full marathon for sure. (Heck, if I have fun in Cleveland and can stay in marathon shape without sacrificing too much summer cycling, I may do it anyway. )

I hear good things about Disney (January), with the exception of the extended pre-race corralling. This year was definitely an outlier as far as the temperature. Chicago does look like a great time too!