Benny's thread got me researching boots. I currently use felts, studded felts, and/or sticky rubber (patagonia) depending on the river I'll be fishing.
Here's a good thread on wading boots for those looking for answers. It even has a Korker's rep answering some of the questions.
Rubber or felt? Cleats or not? Type of cleats? As for me, I'm a felt kind of guy, but I found the dialogue interesting.
http://www.west-fly-fishing.com/forums/ubbthreads.php?ubb=showflat&Number=630033&page=1