[Olog-hai]

My introduction to Mingus was his Blues & Roots album. He was way more diverse than that musically, but this was quite a heavy album in terms of instrumentation.

[Lurking Libertarian]

Blues and Roots is probably Mingus's most accessible album for jazz newbies. Most of his 60s albums are pretty great, as are some of the 70s albums (especially Changes One and Three or Four Shades of Blue).