The best rhythm guitar is the one you like the best. John Lennon probably used a solid body Rickenbacker and a hollow body Epiphone more than anything else. David Crosby seems to have used a Gretsch hollowbody often. I like the Les Paul but I'd probably go with a Taylor T5 if I were going to play mostly rhythm. My second choice would be a Carvin AE 185 with the optional coil switches (they give one the choice of dual or single coil sound). You have to decide which is the best rhythm guitar for you.
http://www.carvin.com/products/guita...emNumber=AE185