One thing to keep in mind, nothing breathes better than Goretex. The Guide Pant is obviously the choice if that's important to you provided that you're willing to part with that kind of cash. Simms does have a pant offering other than the Guides but they are Torray, not Goretex.
If you are not going the Goretex route, lots of other options will be available. Orvis has the Sonic Seams I have the waist highs as a backup/warm weather pair and they work pretty well as far as comfort. They also make a waist high version. Very lightweight yet reasonably durable all things considered. This is the same technology used in the Redington waders. Good pants, but again, nothing I have ever owned breathes as good as Gortex.
~*~Leave only your footprints~*~