I would recommend the Marantz MM7025, which is quite good and only $799, or the Vincent Audio SP331, which is really excellent for $1399.

A properly refurbished Hafler 200, 220, or 500 plays well to the strengths of the Martin Logan sound. Depending on how loud you listen Martin Logans also love tubes. Something about a transformer driving a transformer, I guess. But I've heard it a few times in Hi-Fi shops. There are few GTA SE-40's for sale by members of the GTA Yahoo forum right now. Some of which have been updated by Jeff at Sonic Craft. I used a Sonic Craft updated SE-40 with a few fairly inefficient speakers over the years and you'd have to spend well into the thousands to get a better amp.

Arcam also makes a wonderful power amp that does't often get allot of consideration because they are usually used as extension of Arcam integrateds or HT Amps. They are really great amps.