Without checking the specs for each of the amps mentioned thus far, I suspect that they ALL meet Magnepan's recommendation. One of the Maggie dealers claims the iNova (not the original, although that may well be fine too) is ideal with the Mini Maggies - just passing that on. I completely understand why Magnepan cant make blanket recommendations - no two rooms/listeners are the same. We had an extensive discussion re Maggies over at AK, and one of the guys claimed his ML Vista hybrid 'stats ( http://www.martinlogan.com/products/vista ) cremated both the Mini Maggies and the 1.7 - sadly, that's 4K worth of speaker and it wont fit on a desktop. As for the LS50, for all the rave reviews you would need to hear them for yourself - at least they are closer in price to our friend's MLs. Personally, if I ever grow a set, it will have to be the 3.7s - death or glory.
The power supply is "what separates the men from the boys." A receiver is very efficient and cost-effective way to get is all in one package, but there are "issues". Unfortunately, consumers want all the "bells and whistles" without understanding the importance of power supply. Many manufacturers offer the "bells and whistles", but, compromise the power supply to be price competitive. There are a few manufacturers that are the exception.
Everyone understands they need plenty of power, but the role of power supply is not understood. There is one important concept you need to understand when shopping for an amplifier or receiver---and it is somewhat like understanding "good" and "bad" cholesterol. The ratio is very important. An Gold Standard for an amplifier would be to double the power at 4 ohms. This concept is important even if you are buying an 8 ohm speaker. If the amplifier is rated at 80 watts at 8 ohms, it should (ideally) produce 160 watts at 4 ohms (or close to it). None of the receivers will do that. However, this is the benchmark of a good amplifier design. A 10 watt amplifier that produces 20 watts at 4 ohms "speaks volumes" about the PHILOSOPHY of the designer. (But, of course, it does not tell you if a 10 watt amplifier is enough for your room.)