I'm kinda new to the plannar/magnepan world, but I am really interested in trying out a pair after all the reviews I've been reading. From what I understand these speakers are quite power hungry. What is the minimum I need to properly drive these? 
I currently have a VAC Avatar integrated tube amp. These are the stats:
Type: Integrated vacuum tube amplifier with MM phono stage and home theater (direct power amplifier) mode.
Tube Complement: two 12AX7 low noise (phono), two 12AX7 (line stage), three 12AU7/6189A (power amplifier), and four EL34 (power amplifier)
Options: Remote control for volume (motorized direct control) & mute
Power amplifier ("Home Theater" direct mode):
Output matching: 4 or 8 ohms nominal
Power output: 60 watts/channel ultra-linear; 27 watts/channel triode
Frequency response: 9 Hz - 35 kHz +0 / -0.5 dB, 3 Hz - 71 kHz +0 / -3.0 dB
Power bandwidth: 11 Hz - 63 kHz + 0 / -3.0 db ref. 50 watts
Gain: 25 dB ultra-linear; 23 dB triode
Residual noise: 1.5 mv at 8 ohm output
Channel separation: -72 dB @ 1 kHz; -60 dB @ 10 kHz
Line stage preamplifier:
Gain: 24 dB
Maximum input signal: Infinite (attenuation precedes line stage)
Noise contribution: Approx. 0.1 mv at power amplifier output 
THD contribution: Approx. 0.04% 
Tape output: Unity gain from selector, non-inverting 
Phono stage preamplifier: 
Gain: 37 dB (measured at tape output)
MC phono stage in place of the MM optional 
Residual noise: 3 mv at output (S/N ratio approx. 69 dB) 
Overload: 117 mv @ 1 kHz = 8 volts RMS output, 460 mv @ 10 kHz 
Frequency response: RIAA +/- 0.25 dB 
Notes: Does not invert absolute phase. 

Anyone know if these will do or if I'll have to upgrade? Love the tube sound . . . will I need to go solid state for Maggies? Thanks for putting up with the noobie question :) 
food for thought......I am pushing the 20.7's with the Devialet Expert Pro 1000's .  These are hybrid class A/D technology and I could not get Magnepan to provide an opinion.....but comparing to other amps i have owned IMO they sound the best they ever have......  using the Berkeley Ref DAC to that may be helping greatly.......


     I agree that the Bryston  28BSST2  mono-block amps would probably be the best sounding amps for Natureboy's 2.5 speakers.      
     The bad news is that a pair of these mono-blocs new were about $15,000  (Natureboy didn't state his budget but I assumed it wasn't unlimited), they're huge and weigh about 100 lbs/ each, are very inefficient and emit a tremendous amount of heat.

     Good class D mono amps (such as Wyred, Bel Canto or D-Sonic), in the opinion of 6Moons reviews, are about 90% as good at 1/4 the price or less. Plus they're small, weigh about 10 lbs/each, are very efficient and emit very little heat.  

     Natureboy will need to decide which factors are most important to him.



The best amps are the ones I have now, Bryston 28BSST2
runner up, Bryston 7BSST2
after that in order of "best sound"
Pass X350.5
Stewart, how would you describe the sonic difference between the 7BSST2 and the Pass 350.5? I am toying with the idea of  buying either the 7B3´s or a Pass 250/350.8 for my 3.7´s.
Alot of great info above , I sold maggies for yrs and ran many tubes and ss through them ( lots of free time at the ole’ brick and mortor ).I have also owned most of them over the yrs except tympanis ,that being said i ran cj personnally and biamped the low end with ss ( bryston, krell ,M.L , cj luxman etc ) am a big vac fan and believe it will drive them .It will run out of steam , but will be magic at med volumes if they are properly setup and the room is treated well . The phi 110 vac will bring more power . With planers power usually is your freind lots of it imo .Personally i always found tube top ss bottom was the juice for planers ..which you could do with your vac . Maggies sound best when they can breath,they can be very placement sensitive . i am in a med room now or i would have 3.6 maggies .. and here i go purist dont throw stones please : ) but i alway ran two fast powered subs also ..jazz rock etc ... jmho
good luck
Noble 100,   Actually, they are about 20K new

I'm not giving him the info to say go out and buy a 2KW pair of monoblocks......I am giving him the information to illustrate that in my experience and flea watt tube amp is not a great option.......I have never heard a Class D amp I liked, but others will have differing opinions, but between a top flight class D and a mid flight tube, I'd probably go Class D also......