My recommendation is, as you will be mainly doing hills, is to focus more on the weight than the aero. I would suggest something with sealled bearing hubs(typically lighter than cup and cone systems), aero spokes, and rims with a 30mm-40mm deep aero profile. If your looking at alloy rims, don't go over 30mm as they start to get heavy but carbon rims you can go up to about 40mm with not too much of a weight penalty but still getting a bit of aero advantage.
The other thing to consider is, if you are doing hills and you get carbon rims, is the potential for the rim to over heat during braking. Some are more prone to it than others but still something to consider.
Stiffness in the wheels is also important because if the wheel is flexing around then not all of your power is getting to the ground. So ensure that the wheels are appropriate for your weight and power output. No point in getting a 1200g set of 16/20 carbon wheels if your a 100kg+ powerhouse sprinter.
What I'm going to build for myself is a lightweight set of wheels for doing endurance, hill events, such as the 3 Peaks in Victoria. Sealled bearing hubs, DT Swiss Aerolite, alloy nipples and 28/32 hole Stans Alpha 400 rims. Heaps stiff and durable due to the high spoke count but quite light due to the very light rim. I went with the 400 as opposed to the 340 as my weight ranges from 80-85g so I wanted a bit more stiffness in the rim. These will come in about 1550g with skewers. I could of dropped the spoke count to 24/28 but I considered the extra stiffness and durability offered by having the extra spokes out weighs the extra 35g in spokes.