I like Grateful Dead almost as much as Pink Floyd, and that is saying something. While some of their studio albums are very good (American Beauty, Blues for Allah, Workingman's Dead), they are mere shadows of the band heard live. I think most people who love Pink Floyd would love the Dead, but people rarely manage to get into the band because they listen to studio albums rather than live albums, and their great performances.
You can legally download their live concerts, check out
www.gdlive.com for mp3s and SHNs (lossless audio). I reccomend anyone interest to check out 27th August 1972 first of all. You will be blown away like you were when you were discovering new Pink Floyd albums all those years ago.