How about using a Denon AVR5800 with Martin Logans

The Denon will not drive impedance loads as low as most Martin Logans go. (1.5-2.5) The denon is not intended to drive loads lower than 6 ohms. You might get lucky at 4 ohms for a brief time but I would forget about Martin Logans with that combination.

JC,
That's not true, before I bought my present 2/5 channel set up I had a Denon 2700, that drove 2 sequel's, a Logos, and 2 scripts in the rear. Never shut the receiver down once! wasn't real dynamic, but it worked.

I stand corrected. I still maintain though that logans dip to around 1.5 to 2 ohms at about 20khz. If you call Martin Logan and ask them if a receiver rated at 6 ohm minimum load will "properly" drive their speakers to their maximum potential I think they might better satisfy your quest for knowledge. I do know Denon doesn't recommend loads at below 4 ohms because I own a Denon and even went to the manual last night to verify. This is a quote from the manual.
"Speakers with an impedance of from 6 to 16 ohms can be connected for use as front and center speakers"
"The protector circuit may be activated if the set is played for long periods of time at high voulmes when speakers with an impedance lower than the specified impedance are connected".

I had an old Onkyo thx-919 and it also drove my logans, Sequel II's,Logos and Aerius as surrounds, as Statman stated, it worked It never shut down, but I did not realise how much better they could sound until I got my separates...

Onkyo receivers actually are rated to be able to drive 4 ohm loads. Onkyo has much more current capability adn able to drive lower impedance load than Denon. Even my Yamaha will and is rated to drive 4ohm loads.