1,2, 3, back 3, jump 2, 3, 2 mace charge for 34% (37% with one bar if you MB mace charge).
There's a ton of bnb's in the thread Sunfire posted above and be sure to check out. Look at the Battle footage thread for ideas too as you get to see a variety of different Hawkgirl playstyles.
General discussion is great too.