what makes a guitarist great is based too much on opinion to say one way or the other. i mean naturally there are people who can play like crazy but cant really write anything interesting. i'd rather focus more on the point of a good songwriter and musician than their technical proficiency at whatever instrument. i dont care how fast and perfect you can copy a jimmy hendrix or eddie van halen solo (you have skill, dont get me wrong), but if you cant write your own songs that appeal to me on some level or anyone...then you arnt a good musician. i personally dont think eddie van halen is a good musician because everything he plays sounds the same...jimmy hendrix is a great musician, im not into his music, but he has some great song. again, its all based on opinions but i'd rather focus on the songwriting than the specific part of the song, a.la. - specific instrument.
also, effects are part of the instrument and if you write a song with effects and get a good tone and can get a nice mood across, then it doesnt mean you suck just cause you rely on those effects. its part of the song, most songs would suck without the right tone. i doubt some of the acoustic beatles songs would be nearly as good if they were done through an electric mandolin...or maybe they'd be good in a different way...i dunno, but you see my point?
just listen to what you want and never stop finding new music. thats the one mistake people make, they get closed minded on music and different styles. just be open to everything.
in my opinion...
Radiohead's lead guitarist is amazing because of the tones and different moods he can accomplish as well as some of the catchy ass rythems he writes. im rambleing now, so someone else comment....