There are only five albums proper, so it's not going to set you back too far to get the complete works. I like Bossanova and Come on Pilgrim as well. In fact, the only one I'm not too keen on is Trompe le Monde, and even that has its moments. Doolittle and Surfer Rosa are the essentials, though.
Manny and Otto were both right on. Bosanova is also a great album and my wife's favorite. I'm actually a huge fan of Frank Black and the Pixies. If you want to buy just one of the Frank Black solo albums, "teenager of the year" is a good place to start. 22 songs I believe covering a wide range of styles that showcase Frank Black's brillance as a songwriter.
Pixies Rock! I like Trompe. Hang Wire is genius. Havelina, This Monkey's Gone to Heaven, Where is my Mind? etc ... all great titles to check. But would advise start with Surfer Rosa. If you download, try the superdrag cover of Wave of Mutilation. Awesome. There's an interesting compilation of covers called Pixies Must Die. Some gems.
Pixies?... nah... just start your Frank Black collection now. Frank Black is Black Francis from the Pixies, after they broke up he went on to release several solo albums that just kick @ss! Start with Frank Black (orange cover, self titled) and end it with Black Letter Days and Devil's Workshop (his last two releases, released together at the same time, why no double album, you got me) and be sure to get all the ones in between.
I agree, but I certainly don't think those two are the most "listener friendly." If I was trying to turn someone on to them, I'd probably start with Trompe le Monde or Bossanova. I think as a whole, those are their two most listener friendly albums. In fact, out of those two I would say you should get Bossanova first. The songs seem to get sillier and sillier as Doolitle goes on; although, that is still my favorite Pixies album.
Frank is cool. I have a lot of his albums. But the Pixies are beyond essential... you definitely want to start with them before you go with Frank solo. Kim Deal brought a lot to that band.
Personally I'd go with Surfer Rosa, mainly because you can spank it to the album cover... Otherwise, it's a coin flip between that and Doolittle