I haven't bought a Santana album since Supernatural came out. That wasn't a bad album, but he didn't need to do a bunch more of the same format. IMO, Guitar Heaven is just an all-covers rendition of Supernatural.
If Carlos decides to do something a little more in the vein of his first three albums, I might buy it. Otherwise, I'm not buying another one of his discs.
Who said anything about buying it? The Internet and Rapidshare is your friend!
Check this out. The intro's not that hot, but when they get to the jam it's pretty obvious who's on guitar!