Trek and Topeak both make a rack/bag system. So that the matching panniers and trunk bag snap on and off in seconds. Neither will win the bag of the year award currently being fought over by Ortlieb and Arkel.

But if your not looking for top end, and costly, bags, I'd recomend either the trek or topeak and probably one of their trunk bags. Both will do you fine. Heck I use crappier version of treks bags, and have about 12000 miles of commuting on them thru a LOT of rain, and they keep working enough that I cant justify replacing them. Oh and they usually come with built in rain covers.