Hi
When you say FruityLoops, do you mean the current FLStudio series, or the older step sequencer style? If you want a step style sequencer, you may like Octamed.
I think for more modern style sequencers, BarsNPipes is probably the most popular, and still has a reasonable user base. I think there is a Yahoo Groups community for it, and there is a handy 3 bank x 16 channel midi interface available for it. I believe Bars N Pipes is also free software now.
I always prefered Music-X 2, as I found it more intuitive. It's not so easy to get more than 16 midi channels with it, though.