I use TradeStation (as does LG, and I would suggest you ask his opinion), and love it. IMO it has everything, making subscriptions to other sites (r-t charts, news, backtesting and scanning sites, etc.) unnecessary, and the fills are excellent. Love their charting capabilities and large selection of tweakable indicators. I've had it for like 2 or 3 years and have only had one significant downtime that I can recall (very reliable platform and datafeed). Of course, you pay a fee for what you wish to include, though commissions are low.
I also use Interactive Brokers as a backup and they have the lowest commission schedule I'm aware of, but are a barebones platform, awkward to use, IMO. Good for trading pennies, however.
Good luck in your choice.
Newly