Favorite Tribute Albums?

I like Return of the Grevious Angel - Gram Parsons tribute

Good one.  I particularly enjoyed Lucinda Williams cover of the title track.

I like Cover Me, featuring covers of Bruce Springsteen songs. PBS did a program called Bruce Springsteen's Nebraska:  A Celebration In Words And Music  that I have not heard, but I would like to, if for nothing else, Lucinda's cover of Born In The USA.

And speaking of Lucinda, she did some interesting cover CDs (Lu's Juke Box series) which included cover cds of The Rolling Stones, Bob Dylan, Tom Petty; but I haven't listened to them much yet.

I've got several tribute CDs . . . I'll have to go back and look through them.  I think I still have Steve Earle's tribute cd to Townes Van Zandt, and there was some stuff on that I really liked.

. . . Timeless, the Hank Williams tribute CD, had some interesting covers by some great artists.  (I bought that one for Cold Cold Heart covered by Lucinda Williams, but it also featured Bob Dylan, Johnny Cash, Sheryl Crow, Keb Mo, Beck, Mark Knophler with EmmyLou, Tom Petty, Keith Richards, Ryan Adams and Hank III.)

Oops.  On edit, I see that the OP already picked Timeless, but I second that nomination.

. . . Steve Earle also did a tribute to Guy Clark which he titled Guy, and I honestly was not familiar with Guy Clark's work, but I did like Earle's tribute CD.

I'm Your Fan, The Songs of Leonard Cohen - Various artists covering Cohen's songs.