I'll go w/ "Memory Almost Full"
Doesn't reach the heights of "Ram", "Band On The Run" or "McCartney" but along w/ previous album "Chaos & Creation" (my favorite), it's arguably his most consistent album. Some of the material gets pretty lightweight towards the end but it manages to avoid feeling overly simplistic or tossed off. Like Trung said, the only real problem w/ the album is the mastering, which sounds like it was done by Steve Wilson on PCP
Aside from "Band On The Run" (which is clearly a cut above all other Wings albums and one of Macca's best), I consider the Wings studio albums I've heard (all of them except for "Speed of Sound" and "Back To The Egg") to be of a similar overall quality, even though they each have different strengths and weaknesses. Generally speaking, I much prefer solo Macca to Wings.