Type "broker comparison" into Google and you will get a bunch of pages like this...
www.scottrade.com/online_broker_comparis...omparison|3266289457
Check them out and you should get a feel for the different brokerages and what they offer. Although these are competitive marketing materials they are reviewed by the FINRA organization and they can face serious penalties if they lie.
HOWEVER, commissions are usually the least important issue in my mind. I am much more concerned with service. Call them all and get a feel for how they treat you and answer your questions. You may not need to talk to a broker very often but when you do - you really do.
--- My opinion