Hi. I recommend getting a Denon 4311 as your processor (and to power surrounds if you choose).
Why a Denon over a Yamaha? I'm sure
both are fantastic choices, but the Audyssey SubEQ and MultiEQ XT32 are a big advantage of the Denon. If you're running all separates amps (even for surrounds) you can also turn off the amp circuitry on the Denon which will mean cooler operation and longer life time.
Does it really, really matter what you choose? Of course not. Whatever you pick though, make sure it has robust preamplifier outs (3V or more,
preferably 8V or more). The Marantz AV7005
would be my choice if it weren't for its lack of SubEQ (which is a big difference maker).
Now if you feel brand loyalty towards Yamaha, then don't feel too concerned with something like the Aventage receivers. They're a good choice with robust amp sections.
The next issue is a separates amplifier for the Martin Logan fronts. It gets tricky here. On one hand, some people note that their very low impedance as you go up in frequency, can really strain amplifiers. On the other hand, I feel those frequencies are so high up that there won't be much current as music content tends to be all harmonics at those frequencies.
The easiest choice, would be one of these Crown DRIVE CORE amplifiers:
http://www.bhphotovideo.com/c/product/674286-REG/Crown_Audio_XLS2500_XLS_2500_DriveCore_Stereo.html
Which are unconditionally stable under any loudspeaker load and built to last a lifetime.
If you're still intent on Yamaha, then I would pick up one of these:
http://www.zzounds.com/item--YAMP3500S
Which a former member replaced his McIntosh amps with.
Another great choice, would be used Parasound gear. Very current-capable.
My choice, though, would be the new Hypex Ncore amps
