Not a Rockford fan. Had issues with them years ago and never have gone back. Depending on how you have the subs wired, you can go with a 2 channel and a monoblock, or a 4-channel. 4-Channel can be operated in 3 or 4 channel mode depending, again, on how you have the subs wired.
To get the most out of the subs, you might be best with 2 amps. If the subs are 4 ohm single voice coils I'd wire them in parallel and use a monoblock amp. Then a more basic 2-channel for the mains.
Which amps you use are really a matter of budget and personal preference after you establish the required RMS for each set of speakers and how you want to wire the system.
I buy a lot of my stuff here:
http://www.sonicelectronix.com/cat_i...mplifiers.html
I've personally had good luck with JL, Alpine, Kenwood, and Image Dynamics. Never had the $$$ to get into the higher end stuff though, so YMMV.