after going through and updating my beatles collection, here's how i would approach it if you were buying the CDs (and not a complete beatles fanatic):
LPs
Rubber Soul
Revolver
Sgt. Pepper's
Beatles [White Album]
Abbey Road
Comps
1962-1966 [Red Album]
1967-1970 [Blue Album]
(forget about the past masters if you're going this route)
Close Call LPs:
on all of these earlier LPs you'll get the best tracks on the Red Album, but miss some great songs if you don't get the full albums ... it really depends on how much you like the early stuff:
"Please Please Me"
"With the Beatles"
"Help!" (this was the toughest call to leave out)
LPs to skip:
"Beatles for Sale": ehhhhh
"Magical Mystery Tour": you'll get most of the good tracks -- which were just compiled singles for the US market -- on the Blue Album
"Let it Be": a trainwreck, although "Let it Be.. Naked" is a pretty good listen
"Yellow Submarine": two essential tracks, both found on other albums or comps above