The haptic feedback isn't one of those things I'd be ok with turning off. To me, it's what makes the touchscreen keyboard usable. I had terrible battery life through the first few cycles, but it's great now, plus I have an OEM Samsung battery that is at 100% waiting if I need it. It's worth the money.
what I did was turn it down in the settings instead of off. Not sure if it will make a difference. Also I took the advice on optimization here and at android forums and there is a Captivate forum Samsung Captivate Forum
Not many people go there but there are things I found useful. Also Android Forums has lots of good stuff.