Note for note, song for song, I have to agree that Armed Forces is perhaps his best album and a great place to start. "Accidents Will Happen," "Oliver's Army," Nick Lowe's "(What's So Funny "bout) Peace, Love, and Understanding," "Senior Service," "Green Shirt," "Big Boys.' They are all great songs.
His first four albums are essential IMHO.
Rhino put out a great 2 disc collection of hits a couple of years ago. It stretches all the way from My Aim Is True to Painted from Memory. It also has a few Macca collaborations - "Veronica," "So Like Candy," and "That Day Is Done."
And in the end...