That depends on what you want to trade. In Canada the broker with the best platform is probably TD waterhouse, Scotia iTrade is cheaper but what a lousy platform and really bad execution.

If you want to trade US Futures, like oil, (that’s what I do) I use Interactive Brokers. Their support is awful – boarding on rude, their TWS software is ugly, but they accept Canadian based accounts (in US funds only) and they have great execution and low cost. I trade IB with NinjaTrader as the front end. If you are an options guy you might like Think or Swim – more expensive but a great real time interface.

I'd look for tight spreads, good platform, and relatively established name first, then everything else. Don't go for anything crazy like EURUSD spread 3 pips etc :P

IB Canada is probably your best bet to get started. Their margin requirements are high, but that can also keep you out of trouble. Good commissions.

Like was mentioned previous, use a NinjaTrader license to trade from a DOM or charts. TWS is cumbersome and probably not well suited to a thin market like CL.

cheers.