I use Interactive Brokers (as well as, TDAmeritrade, TradeKing, TradeStation and Options House which used to be TradeMonster.)
Interactive Brokers equity trades are only a $1 buck for a round lot. Option trades are 0.70 cents a contract with no base charge. SWEET!! They're the king of cheap.
Their Trader Workstation software is a bit clumsy but allows for fast trading once you get used to it.
Just my opinion on each broker if you are interested...
TDAmeritrade - Expensive, clumsy and they really tick me off sometimes. Executions are lighting fast though. I only have an account to use their Think or Swim platform.
TradeKing - Pretty cheap, kind of awkward website, slow executions.
TradeStation - If you are a programmer and like automated trading, they are the Rolls Royce of brokers. But you gotta pay a $100 bucks a month if you don't trade frequently. Mostly suited for day traders.
Options House - Reasonable price, fast execution and hands down the highest quality website and trading platform. Extremely well designed. They are pretty strict on margin balances if you need that sort of thing. Executions are okay.
