Many people use multiple feeds/platforms
[IB/TWS can only be fed with IB's feed]
Personally I use:
IB/MC [Multi-charts] for my Entry Charts {Licensed Version-one instance only}
IB/MC-DT [secondary IB log-in's with MC Discretionary trader to drive monitoring systems throughout the house]
{MC Discretionary Trader is Free, same as licensed product sans custom indicators and can be run on multiple computers- both MC & MC-DT have Order Entry/Dom capabilities}
IB/BT [Buttontrader] for Order Entry/Dom
TS [Tradestation] for Historic/Research only - convenient, organized, good Historic Data, however, their platform bogs/lags in a fast market, unreliable for Entry [bad experience as Brokerage]
{TS data can also feed MC, Their data isn't bad, just their archaic bloated platform and brokerage}
MC/TS both use easy language so an intuitive combination [for me]
Another good combination is MC/IQF - Reliable/Solid Data - History not as far back as TS
Some prefer NinjaTrader [NT] for charting, its a personal preference between Ninja and MC and the time invested on the learning curve [also has Order Entry/Dom capability]
TS
http://www.tradestation.com/default_2.shtm
NT
http://www.ninjatrader.com/
MC
http://www.tssupport.com/
IQF
http://www.iqfeed.net/
BT
http://www.buttontrader.com/
IB is a very good brokerage, you can't go wrong opening an account with them, excellent 3rd party support as well...
You will need to purchase data for all markets you intend to trade, however, their rates are extremely reasonable, it isn't even a factor
E-signal and IQFeed will be the more expensive options...