Dupli-Color Filler Primer is my choice for surfacing. It is inexpensive, fast drying, and high-build. Although it seems like all hardware or auto parts store sandable/filler-type primers work about the same, that one is my fave, seems to have the highest solids.
The Tamiya primer is pretty outstanding. It is a great surface prep for paint and goes on so nicely it's almost as if you can't mess it up. It disappeared for a while, but seem to have returned. I've noted it is similar to Mr. Surfacer, but since it already comes in a spray can, I think the Tamiya wins.