Great setup!! Do you ever leave it?!
I'd get matching Klipsch to add the channels if you have been happy with that brand.
For a subwoofer, there are a lot of options. Take some time to browse the subwoofers forum and see if something catches your eye, and then make a post in that forum with any questions you have and we can recommend. I personally like Dynaudio (
www.dynaudio.com) and Bag End (
www.bagend.com), but there are many options depending on your budget. Lots of people recommend SVS here (
www.svsound.com). Take a look at what some other people decided on, it makes for some interesting reading.
You said "you can't wait to buy a house" ... is that an apartment? If so, you might want to be careful with buying some of the subwoofers we recommend because they will piss off your neighbors.
Cheers!