Make sure you ask us why we like them, or else a mod's going to close this up quick.
I have a lot of favorites, but I'll just list off my favorites lately.
Killswitch Engage: They're a metalcore band who've gone through two singers, but I love all their stuff. Their guitars and drums are as heavy and fast as any of the metal artists today, but what really makes them enjoyable is their singer's, Howard Jones, melodic vocals combined with hardcore screaming. It really adds a lot to their sound and is just fun to listen to. My favorite songs by them lately has been My Last Serenade, Let the Bridges Burn, Vide Infra, and When Darkness Falls.
Five Finger Death Punch: Another metal group, they're only a couple years old, but put out a great debut album called Way of the Fist. They have an instrumental sound that is incredible and reminiscent of older thrash metal bands. Their singer has an excellent screaming voice and a nice regular singing voice. They play great live too.
I'll leave those two out there for now.