In summertime the answer is easy: rack for sure. (sweaty-skanky-back related reasons like Steve brought up)
Re the front suspension issue, yes it's nice, but I wouldn't call it a deal-breaker. Have you thought of wrapping the handlebars with two layers of handlebar tape? (even if you continue using flat bars, just use handlebar tape instead of grips) That would do a lot to help ease handlebar vibrations and cost a heck of a lot less.
You might find that the cyclocross geometry may be very similar to your current CRX.
My commuter has a Topeak rack that has a special rail in it for a "quick-release" kind of bag that they sell. The bag itself slides on and off really easily, and has expandable little side-bags that are like panniers. It can store a LOT of stuff, the whole thing is very nifty.
The rack:
http://www.topeak.com/products/rack_004.html (non-springy kind)
The bag:
http://www.topeak.com/products/bag_013.html
They have some other rack and bag options of varying sizes and weights, most (if not all) have the quick-release function.