I interned at this club over the summer and I used the shutter drag technique a lot. A normal nights settings would range from 1/10-1/25, f3.5-f4, iso 800-1600. Normally I would bounce the flash off a wall or ceiling, but it depends on your venue. My biggest gripe was the lack of space to get an adequate distance to shoot, so my .02 would be get a decent zoom, unless you feel like switching lenses all night and being uncomfortable. I used my kit lens the whole internship, a zoom with a f1.8 stop would be preferred. Lastly, if you do decide to use a flash, get a diffuser, the Omnibounce diffuser works wonders and isn't a distraction nor is it bulky.
All in all, just have fun with it, you're gonna meet a shitload of people, some will love the picture, some will hate it. Just take an ample amount of pictures to pick and choose the best out of the set. You can check out my flickr for examples, I took hundreds of pictures a night and would only choose like the best 60. www.flickr.com/photos/kshank