All serious stock traders will look at index futures (S&P, Dow, Nasdaq, Russell, etc.) even if they don't trade futures. I trade both. Index futures are regarded by some as "leading indicators". These futures move fast as responding to developing news (such as today's big drop in the Dow in the US house not passing the bail out bill). Most stocks which have a good corelation with the market typically follow the index futures' move, but lag in time just slightly.
Trading stocks, you can trade with cash 1:1. You can trade with margin 2:1, or day-trade (pattern day-trader >$25000 equity) with margin 4:1. Some futures brokers allow you to trade index futures with margin 100:1. There are benefits in leverage. (But this can kill you quickly too if you are new to trading.) Plus there are tax advantages trading futures than stocks.
Depending on what stocks you trade, slippage (spread) and commissions (per-share versus per-order charge) can be costly so you probably want to stay with liquid stocks and higher price stocks. While trading e-mini S&P, the slippage can be minimal and liquidity is fantastic in case you need to get out quick.
Most technical analysis techniques work for both stocks and futures equally well.
If you are talking about commodity futures or currency futures, that's a different story.
