I'm always on the lookout for good backing tracks. Even if you have a band to play with, it's hard to get everyone together when you need to. And you've still got stuff to work on between rehearsals and gigs. I find that having some backing tracks makes it a whole lot more interesting to practice. To keep it fresh, you gotta have some new takes on things.
That's why I was so impressed with Elmo JK's backing tracks. He's a blues/rock shredder from Finland and has created a number of impressive tracks. They're way beyond your typical I-IV-V blues shuffle. There's stuff in the style of Jeff Beck, Gary Moore, The Who, Joe Satriani, Jim Hendrix and more. Check out the videos on youtube to see get some ideas.
He's also recorded a great album called "Unintelligent Designs" and some extra tracks from that session called "Unintelligent Leftovers" (which sounds like what I had for dinner last night). These are occasionally on sale, so definitely worth signing up for his email list. That'll also get you a couple of free songs from the album.
I'm hoping he gets out on an international tour, but in the meantime, feel free to check out what he's got.