OH BOY!!! I just finished my first commute with panniers and it was lovely!!! I have a 15 mile one way trip with about 1500 elevation gain...the temp was about 75-82 degrees. It was a relief on the shoulders for sure (I have done both backpack & messenger bag) ...the panniers was the best so far! I did not even mind the extra weight from the racks. Never felt tippy until I started a standing climb...wooooooo ooops!!! stayed upright

bike - Surly Karate Monkey
rack - Jannd (a little rigging required for fit over the fender and brakes)
pannier - axiom Storm (waterproof!!!)
fenders - http://www.woodysfenders.com/ - custom made...I have an orange colored wood with purple heart wood (pinkish color) swirled through...I will have to post pics
bars - a mountain aero bar by Dirt Head (I think...hubby found them on ebay)

I have a few more adjustments to make then I will post some pics...we are planning on trying some touring trips so it is all decked out...I can't wait to really test it out!