I'll enter my vote for mesquite, or a hickory/mesquite combo for brisket! I'd use 6 oz for your cut. Oak is also great on beef.
Disclaimer: Wood smoke flavor is like a spice, and the flavor it imparts is very subjective! What tastes good to me, in a smoke profile, might not to you. There really is a difference in smoke flavors, and it's up to the individual to experiment and find what is best for them!