Depending on your budget - I'd go with a punch 1000 or punch 800. There are tons of decent amps to run those, but Rockford is a very good way to go. shopping on Ebay can get you great deals - or a crappy amp that you just bid too high for. Try etronics.com - very good deals on new Rockford amps.
You might also want to check out the JBL1200 It's a good stable amp that's pretty cheap. I also like the fosgate amps. I'm running a BD1000.1 to a pair of HX2's myself.It Pounds