There are several good manufacturers of waders. Depending on the number of days on the river and your budget, you can find a decent pair. Definitely get breathable waders made of gortex or similar material. I recommend waders with stocking feet and a good pair of boots versus built in boots, better fit and more comfortable. Key attributes to look for:
Durability - look for reinforced areas in the knees and butt
Accessibility - quick release suspenders or a design that allows you to 'go' without removing all your top gear
Warranty - gotta have a good warranty policy, lifetime if possible
Check out Simms, Patagonia, Redington and Cabelas