Ortilieb and Arkel are really your high end, nice commuter bike bags.

Just make sure you buy a pannier set that offers either an inner or outer small zipper pocket to put in your wallet, cellphone, etc. so that things don't get lost in the depths of your pannier bag.

I have only 1 set of rear pannier bags which I use for every purpose --commuting, touring, etc. It's a mid sized.I use plastic bags to protect my gear...it has some water repellancy without those plastic bags. I use Axiom bags.

For computer you will want to protect it with at least another thin padded sleeve/bag.