I enjoyed both QE Park and Murch. Falls in the north. If you are on a budget, there is an outfit in Kampala that can organize the trip north:

http://www.redchillihideaway.com

I have used these folks and it all worked out very well... understand that we were camping, but in purpose-built huts.

For QE Park, I can't recall the company, but it is across the street from the Emirates airlines office in Kampala on the ground floor of an office building not far from the modernesque mall/cinema.

If you have time, there are daily coaches to Kigali which is a nice small city. Figure about 7 hours - depart mid morning and arrive early evening. If you are American, there is no visa fee into Rwanda, but you'll need to pay $30 to get a fresh Uganda visa upon your return. No problem to get Uganda visas at the border or airport.