Jazz Recommendations.

Assuming that you are meaning jazz in the more traditional vein--as opposed to 'smooth' jazz--this is a fun place to start, although some of the albums will require a more lenient ear if you're not so accustomed to jazz.
http://www.scaruffi.com/jazz/best100.html

A couple others that get my vote:
Tomasz Stanko - Suspended Night
Wayne Horvitz - Sweeter than the Day
Achim Kaufmann - Double Exposure

Enjoy!
Howard

What type of Jazz? It's a pretty diverse art form that spans almost a century. Big Band? Ragtime? Bebop? Hardbop? Free Jazz? Fusion? Etc.?

That aside, I'd add for anyone listening to jazz: Coletrane "Giant Steps".

More later.

I would recommend the following albums because they have enough melody and a blues feeling that a non-jazz person can relate to, but are still first rate classics: The Sidewinder by Lee Morgan. Midnight Blue by Kenny Burrell. Ballads by John Coltrane. Coop by Bob Cooper. They are all still in print and easy to obtain.

I think Boa2's list would scare most neophyte jazz listeners away. Although I love the albums listed I don't agree it's a good start. Too out there for the most part.

If your friend is coming from pop/rock , e.s.t. would bridge the gap rather well.