Hip Hop in general has been in a downward slide for the last decade, in my opinion.
Every once in a while, a couple of albums come out that give me hope.
Here is a review of some of those albums:
B.o.B - The Adventures of Bobby Ray
Very melodic hip hop. Lots of live instrumentation and a rock influence. Rivers Cuomo from Weezer even makes an appearance. He even heavily samples and interpolates Vampire Weekend's "The Kids Don't Stand A Chance".
The sample provided below features the chick from Paramore, and there's a remix on the album that also features Eminem. Not sure why he didn't make that version the single.
Travie McCoy - Lazarus
Perhaps even more melodic and rock influenced than B.o.B, also including a song sampling an Indie hit, "Alright" by Supergrass. This is the solo album from the lead singer (or more accurately, rapper) from the pop-punk-rap band Gym Class heroes, but hey, I'm counting it as a rap album.
Drake - Thank Me Later
There are very few "club bangers" on this album, and the ones that are there are obviously built-in singles.
The majority of these tracks are entrancing, slow and dream-like. Really different stuff.
Again, this is a single, so it's not really representative of the album, but here's a sample.