Originally Posted by Ckindt
Simple answer: a 2-channel amp with unbalanced inputs at 50 - 100 watts/channel should suffice for most.
You only need it to drive your two front wides.
It is nice that the 5010 is available new and will match nicely on an AV rack. I had an onkyo M282 which is basically just an older (and better) version of the 5010 for exactly this purpose but I sold it a few months ago.
The M282 is 100w/ch @ .08% THD, where the 5010 is only 75w/ch @ .08% THD all at 8 ohms. I see the 5010 available for $250 at a couple of places where the M282 should cost half of that used if you find the right deal.
Sonamp (260s/270) and Rotel (RB-960/RB-970) are also a great option for a cheap 2 channel amp in the 60w range used...
I decided that for the rack space I might aswell get a 5 channel amp that is designed for a 5.1 system to run WL, L, C, R, WR. The 5 channel amplifiers have similar footprints to the 100w/ch 2 channel amplifiers. Given that I needed an amplifier anyway to run 11.1 and this gets more heat out of the unit.
I find used Adcom amplifiers to be the best bang for the buck as you can see in my signature...
There are several good used options where you can get 5 channel 100w @ 8ohm amplifiers for $350 or less.
Examples of really good cheap 5 channel amplifiers include: Adcom GFA-7000 (135w), Adcom GFA-7400, Adcom GFA-7605 (really the same exact amp as the 7400 just rated at 1% THD in a new case), Adcom GFA-6000 (3x100, 2x60 but only $200 or so), Rotel RB-985 (either mkI or mkII).
For something flexible used the Rotel RMB-1066 and Rotel RB-976 are bridgeable 6 channel amplifiers that can run either 6x60W or 3x150W @ 8ohms.