I just laced up a velocity A23 for my rear. It's kind of a new model, it's like their aerohead rim, but 23mm wide instead of 19 or whatever. Fairly light, strong, and happily runs my 35mm tires. Or, you can just run their aerohead if you want something a little more narrow. Velocity has a touring rim called the dyad which is popular, and bombproof, but fucking heavy.
Mavic open pros are good, too. You can spend a little extra to get the ceramic ones, they will last forever. I've heard ceramic rims can brake kind of weird in the wet, though. If I were rebuilding a wheel for long rides, commuting, etc. I'd probably go this route.
But, let me ask you: Why do you need an entire wheelset? You can just buy a new rim and have your LBS put it on the rear hub you already have.