Recovery reallly shocked me at how good it was.
Instead of every song just being straight up rapping, there are tracks like Space Bound (one of my favorites), Going Through Changes, 25 to Life, and Love the Way You Lie (although quickly becoming played) that have slower, more "musical" segments to the songs, and they flow.
Also, he raps about things that matter to most of us, and things that most of us can relate to instead of money cars and bitchez. While I do realize that there are other rappers who rap about other stuff as well, Eminem just happens to appeal to the masses, and that's a sign of a talented artist.