Anyone know a good one - that sounds real ! ! ! 
I have been using some roland/yamaha samples that I am not happy with it - it still sounds like a synthesizer with keys, as opposed to an electric guitar with a great fuzz tone.

Which version of Sonar are you using?  TH2 that comes with X2 and X3 is pretty good.

Amplitude 3
 
Try the free version of Amplitube 3 that IK offers and then you can buy each piece of gear (amps, cabs, Fx etc..) seperately at their custom shop. IK might have another Group Buy (they always do) later on this year and you should snag the full version then.
 
http://www.ikmultimedia.com/products/amplitubecs/

I assume what you want is guitar tones from midi notes? Real Guitar or Strum through any amp sim should do it!

Mokafix metal clone.  I needed a good fuzz/distortion effect once for bass and this worked great

Yes - I am looking for great distortion guitar samples, amp sims, etc. - from MIDI notes!

deswind
Yes - I am looking for great distortion guitar samples, amp sims, etc. - from MIDI notes!

Yes, samples of distorted guitar won't work since in the real world, the distortion happens after the strings have harmonized. You need a softsynth like RealStrat or RealLPC (maybe AAS Strum that comes with SONAR X3 will work? I dunno, never tried it) that emulates the way a guitar is played and then output the audio into an Amp Sim like Guitar Rig, Amplitube, Scuffham S-Gear (my favorite) or whathaveyou.

Check out some of the offerings on amplesound.net.  I think their various electric (and acoustic) guitar synths have become the best available.

A lot of it is in the playing technique. If you play the way a guitarist might actually play the part, a relatively mediocre sample through a decent ampsim can suffice, whereas even the best sampled guitar will sound like a keyboard if you simple hammer the line in like you might on a keyboard.
 
It's worth spending some time learning guitar specific phrasings and articulations. Some plugins do help with this by offering short lines or automatic hammer-ons or bends and so on.

Sanderxpander
A lot of it is in the playing technique. If you play the way a guitarist might actually play the part, a relatively mediocre sample through a decent ampsim can suffice, whereas even the best sampled guitar will sound like a keyboard if you simple hammer the line in like you might on a keyboard.
 
It's worth spending some time learning guitar specific phrasings and articulations. Some plugins do help with this by offering short lines or automatic hammer-ons or bends and so on.

+1 from me.
 
Learn how a guitarist plays, and put it through a guitar amp/amp sim.
 
Jan Hammer did some incredible playing using A Moog or a Fender Rhodes.  Listen to his album "Black Sheep" from the late seventies.  It is as much how /what you play as anything else.
 
Someone (I think it was the "Times" newspaper) once asked Jeff Beck who his favourite guitar player was, and he answered "Jan Hammer".