Marantz SR 4001 - has 7 discrete amplifiers rated at 80 watts (you will not likely notice much if any difference between an 80 and a 100 watt amp especially if you are using efficient speakers, if your speakers are ineffecient then you need to be looking at something above 100 watts anyway.) Should be able to find one in a store for around $500. The 100 watt Marantz model costs twice as much, is twice as big physically but has a few more features. Look to pay about $1100 for one of these.
Yamaha RX-V461 is rated at 500watts (total wattage of all amplifiers don't think for a minute this rascal can pump 500 watts into one speaker) and is 5.1. Price for the Yamaha is around $300. I like Yamaha equipment.
Denon AVR 887 may be your best bet at around $700. it puts out 100 watts and is a 7.1 receiver.
Onkyo TX-SR705 will set you back about $800 but it has that 100 watts per channel you covet but it is a 7.1 receiver.
Hope this helps a little. The only way to really make a choice is to go listen to each of them in a controlled enviorment not some big wide open space like a discount warehouse. See if you can borrow one to demo at home or get them to agree to a money back trial.
My home theater uses an Adcom 3 channel 250 watt amp for the front main and center chanel speakers with an Adcom 100 watt stereo amp for the rear chanels, subwoofers are 15" DT with built in 400 watt servo amps. Signal processor is a Lexicon DC2.
Please add enough into your budget to purchase decent speaker wire and interconnects.