There are many options at $200, and you see tons of the Mavics around, which I think is a testament to them. If memory serves, the CXP series are the more aero profile, vs their box rim series. Remember that wheels are a totally portable upgrade, so whatever you buy is never wasted even if you later get a different bike or set up.

I bought a set of Easton EA50's (which are about $400 list and I got for a steal) and they were a fabulous improvement over the stock Alex rims. Consider your wheel budget, and more spend, IMHO, does yield more improvements, at least in feel for me.

You might also want to check out a shifter upgrade if you decide to upgrade the current rig. I went from low end Shimano to SRAM X9 and they are phenomenal. The X9's are the lowest level with the direct acting shifters in MTB components (or zero loss or whatever they call it) and they shift like a dream.

You should also take all of my advice with a grain of salt. In the past 18 months, I bought a bike new, swapped for another new bike, replaced every component on the 2nd bike except frame and fork, bought frame and fork and moved all upgrade components too it, bought parts to change it to drop bars and then back to flat, bought another frame and again moved all of the parts, and changed the previous bike to a single speed. I am extremely decisive for very short periods of time.