you would be moving from more of an am class to a xc/ trail class. it really depends on the tire you want to run.
Oh which rim you have already.
I like Bontrager Mustangs. Good, stiff XC rim, light and durable. I got a set of 29er rim brake ones, and my main complaint about them (and it's a pretty substantial one) is that the sidewalls are pretty tall, so it pinch flats easily at lower pressure in areas with pointy rocks and roots. I have to run an extra 3-4 psi over what I normally run to keep them from pinching.
I had the Disc Brake 26er version, and I beat the tar out of them for years with no issues. They did not have the pinch flat issue like the 29ers rim brake one does.