For Z-ro, I started listening to him right around the time he released Crack, he's been naming his albums after drugs (Cocaine, Heroine) ever since then. My favorites by him are True Hero Under God, and Still Throwed (w/ Trae), which were before Crack, though.
I haven't heard much of Chamillionaire for a long time, don't know if he's released any new albums, but yeah, I've listened to him quite a bit.
Some people I've ran into don't like Slim Thug, not one of my favorites, but I think he's good. I think last year or the year before was a good year for him, though I haven't heard much from him either. Trae is a little hard to understand because of the speed he raps at (

), but I think he's good when paired with Z-ro.
Haven't tuned in to new songs by some of these guys lately, I usually go on youtube for that.
