I use scottrade, it's cheap ($7/trade for regular, stop and limit trades).
Also, no minimum account balances, signup fees, montlhly mininum fees or account maintenance fees or any of that kind of BS.
They have tons of info, but little guidance. So basically, I get my investment info/guidance from elswhere (
www.fool.com is one place , I'm signed up for one of their monthly newsletters) and trade online with them.
Their online streaming ticker and trading is great, and almost frightingly quick. One conformation message (sure you want to buy 100 shares of ABX at $XYZ) and you've bought it a tenth of a second later.
Their recordkeeping is good, they keep all your activity online so it's easy to go back if you need stuff for tax records ,etc.
Don't have any experience with the other ones, so I might be missing something, but I like what I've got.