Also note that you need to stir up sand to prevent gas pockets from forming. MTS will keep your sand stirred if you get some. Also i heard that sand is bad for plants if you plan on getting some since it packs down and prevents water from running over their roots.
I have sand substrate in all my tanks and all my tanks are planted. I haven't found that sand inhibits the growth of my plants, in fact, quite the opposite. As Sincrisis points out, in order to keep anaerobic gas pockets from forming a gentle stirring of the sand at water change time prevents this.
I have sand in 2 of my tanks and really love the look of it. Just a quick tip...make sure your filter intake tube is a few inches above the sand so none gets into the filter. Also, turn off your filter when you do water changes /sand stirring for the same reason.
I have a sand tank and its planted, Kimmie is right, In less then 2 weeks ive gotten ALOT of new growth from the plants I got, the tank they came out of was gravel and soil, the seller remarked on how quickly the plants have grabbed ahold of the tank and started really branching out.
Try it, you'll like it. Plants love it and I think the fish prefer it too. I doubt I'd ever consider anything but sand, I like it that much. As jeaninel pointed out...turn off the filter at w/c time and place that filter intake tube at least a few inches up off the sand. Muy importante!