For lyrics, I would recommend The Ballad of John and Yoko, Get Back, and Come Together, although personally i also love their earlier, more simplistic stuff :0) You might want to try Some of John Lennon's solo material as well.

I think with the Beatles, what's attractive is not the music or lyrics in isolation, but, as you said, a 'sound'. It might be an idea to buy a 'best of' compilation, 'The Beatles/ 1967-1970' would be A good one to get, i think. It's got a blue cover with a picture of the band looking down off a balcony. It has all the songs i mentioned above, andf some other crackers like 'Don't Let Me Down' on it. Either that or get a Beatles loving friend to make a tape up for you, and listen to it in the car or something, it might just grow on you if you don't force it :0)