FYI,
You won't get as good clearances with an Ameritrade, e-trade, etc. The majority of your time they will send your trandes to be executed on a secondary exchange (Pacific, Boston, etc) rather than on the NYSE. If you're dealing with even medium size trades (1/2 lot), your cost basis will be lower with a quality brokerage house because they'll save you an 1/8 or 1/16 here an there. Now with decimalization good transactions are even more important.