Since it seems we get someone asking "what is the best discount broker?" about once every two weeks on these boards, I find it prudent to offer this link for the purpose of aiding the answer of this question.

http://articles.moneycentral.msn.com...neBrokers.aspx

Feel free to offer your own personal experiences with those you currently use or have used in the past and hopefully this thread will be the one-stop-shop for the myriad instances this question will be asked in the future.