I don't know how much of Beats Rhymes and Life is completely his work. That whole Ummah collaborative makes it a bit nebulous in terms of who's responsible for which beat.
I'm actually not hugely familiar with the Roots other than a few obvious cuts and haven't heard that album/track.
Well shoot, what can I give you as a good Dilla primer? It's hard because you can't necessarily list albums. he might've done a couple tracks on a record here and there... it's not the most cohesive thing to get a hold of (which sorta makes it more fun if you get into it; same goes for Madlib, my other fav DJ).
I think a good way to get started is listening to J Rocc's (a solid DJ in his own right) series called Thank You Jay Dee, which is just a mix of a bunch of his beats, instrumental at times and w/ rapping at others. My personal fav of these is the third one: https://soundcloud.com/jdilla/thank-you-jay-dee-act-3
that might be the best way to get a feel for his entire body of work. Too bad Sidebottom's not around; he'd give a few ideas on this too. If you want an actual release to try, maybe the Ruff Draft EP, which features Dilla rapping. It's really short but pretty nice all the way through.