Been streaming smoothjazz.com using Winamp since 2002, been listening to Watercolors on XM since 2003 (and Jazz Cafe on Sirius when they were separate companies). While it mostly all sounds the same to me, I can pick out Michael Lington and his sax in a second.
If you like a broader variety of Jazz (from Dixieland to sounds that only Jazz musicians could appreciate), give a listen to KMHD.org. They have been operating on the campus of Mt. Hood Community College in Gresham, Oregon for a long time and went into partnership with the area PBS group (Oregon Public Broadcasting) a couple of years ago.
Just don't try to listen during a pledge period.
I'll be listening to the "Trad Jazz Show" later this morning.