Front and rear amps


I am ugrading my "stereo" to home theater after many years. I have an old B&K ST-202 modified by Sound Unlimited along with a B&K MC Sonata 10 preamp. I realize I will have to upgrade the preamp to a new preamp/processor. I am wondering if I have options with the amp. Can I use it for the rear channels and get a new 3 channel amp for the fronts and center. Do they need to be from B&K or can I get something else. Or should I just get a new 5 channel amp. I'm still auditioning speakers but I am leaning towards Magnepans. Any thoughts would be appreciated.
hear4
Thanks for the input. I'm still looking for speakers and haven't made my decision. I listen to music most of the time and I like the Magnepans for that (I'm looking at the 1.6 by the way). I think I'll be fine with the B&Ks in the rear. Any suggestions for a three channel front amp. I'm considering B&K, Bryston, Anthem and a few others in the 100-200W range. I'd consider Krell or McIntosh if I can find a used one for less than $2,000. I've heard that some of the older McIntosh which would fit my price range aren't that good.
I just finished breaking in an Anthem MCA 30 that I'm using to drive my LFC speakers. It's mated with a Classe SSP 30 and it sounds wonderful for Home theatre and 2 channel. If money is an object(and it generally is) then value for dollar the Anthem is a great buy for thousands less than the B&K and Bryston.
I am partial to Aragon, I had a similar situation with Maggies and an Aragon 2 channel amp. I almost changed to a conventional box speaker and then found Martin Logans to be a great compromise. I kept the 2 channel 4004 and added the 3 channel 8008x3 that gives me 200 each channel. I would keep the B&K and look for a used 8008, it will drive anything. Martin Logans are great if you have the room to place them a couple of feet of the wall, and you have a wife as understanding as mine. Once you get them in the theater watching movies with the kids they really do not care what they look like if you have room, and if you are considering Maggies you must have room.

I have a Meridian 561 processor that I have been very happy with, but am considering Aragon Soundstage Ultra One. Anyone reading this have any experience with these side by side?