I will be the first to name The Boys.
George really was a rather good lead guitarist. He was not the best, by any means (Clapton, Hendrix) - yet the afore mentioned two WERE rather influenced by the quiet one. John's actually played a rather mean and (I think) underrated rhythm guitar. Paul could play a very mean bass. While Ringo was not anywhere near the best drummer, I think he was pretty underrated steady drummer. Sometimes all a group needs is a good drummer who can keep the beat. All four were pretty good singers. And tying the group together was the rather stoic, yet daring and experimental George Martin, willingly taking the group to areas many feared to tread.
I'm with you there. George was a great lead guitarist simply by virtue of his progressive playing. You hear the riffs from the early Roll Over Beethoven era and they're really good, but when he gets to the Let It Be era, he's damn near unstoppable. Some of the progressions he came out with are fucking amazing. Personally, I think John is one of the most underrated guitarists of all time. The rhythm to I Saw Her Standing There and I Feel Fine both are both amazing mostly because of the rough, almost messy tone he hits, but you look at Get Back, Dear Prudence, or I Want You, and he's playing clean as can be, just another instance of his versatility. Paul may be the finest modern musician simply because of what he could do on ALL of the instruments. The bass lines on Why Don't We Do It In The Road, to the guitar in Blackbird, to the piano in Martha My Dear, to the drums in Back In the USSR and Dear Prudence, Paul can pretty much do it all. Ringo, I personally find to be incredibly underrated, but mostly because of his ability to blend drum patterns into the melodies he played under. Most other drummers try to make the drum patterns stand out, Ringo did the opposite, to the point that they're unique in adding to the rhythm guitar and even lead of many of the Beatles greatest songs.