Although my dress was full-skirted with a train, I really wasn't keen on the idea of an elaborate bustle. I actually didn't want one at all and had to be talked into it (of course, my tailor and bridesmaid were right – the dress would have been trampled on all night long if I'd gone without). My dress was dramatic, but it was a simple shape and I didn't want to complicate it. Sometimes, even if you're not sure what you do want, it can be helpful to be very clear about what you don't.
French and Austrian bustles are fancy and they'll gather the skirt of your dress (they look beautiful on lace), whereas a ballroom bustle will draw the layers of the dress in to points on your waist so it's not as easy to detect. Of course, the more elaborate your bustle, the more expensive it will be, so make sure you're factoring in any extra costs.