Westside!

The east coast is obviously the best region for rap. But the 2nd best region is obviously the West-Side!, specifically California. Especially if you include the artists that aren't rap, but have some rap steez & influence in their music, like Ozomatli, Linkin Park/Fort Minor, Rage Against the Machine, Santana, & The Red Hot Chilli Peppers.

But forget that & just focus on the "strictly rap" artists. If you count mainstream & underground, Cali NEVER FELL OFF son. Check all the quality rap artists, & note I'm only including those with an album released since 2004, to limit to what "the West is doing currently":

Blackalicious
Cypress Hill
Delinquent Habits
Dilated Peoples
Ice Cube
Jurassic 5
The Alchemist
The Coup
The Game
Zion I