ok i shoot alot in the clubs.. you can check my flickr site for examples so ill give my 2 cents worth on my technique. When i shoot in nightclubs, what i want is to capture the ambient light textures like the strobes and discolights so on and so forth.. so therefore i want my shutter speed to be longer.. but at the same time exposing too long a shutter speed will definately cause motion blur, especially if i dont shoot static people.. so id say a shutter speed of 1/4 to about 1/15(set manually) is usable at ISO 400.. sometimes i want rich colors i even go as low as ISO200. Because you are not shooting studio, you dont need tack sharp photos so a little motion blur plus flash freezing the subject is acceptable.. of course flash as mentioned above is set to rear sync.. so now you have your subject exposed AND ambient light textures. The wonders of TTL will help you out with exposure not to worry. I usually set aperture about 3.5/4 and it gives a good balance. Having a fast lens is a misnomer.. it does nothing for you because you DEFINATELY need flash.. It just so happens good pro sharp glass is 2.8.. but kit lenses like 18-70mm which i use produces results nonetheless. The only thing 2.8 glass helps you with is autofocus.. as mentioned above, a good body gives an advantage in things like continuous focus with many AF points to lock on moving subjects. But i still get results using my D70s so its not a must have. Bounce flash in a big club like MOS where i shoot is useless.. but i use it anyway to diffuse the light. i because i shoot up close. This is another thing. my favorite lens is the 12-24mm. Shoot up close for best results because flash and tele wont do s*it in the there. i tried 17-35mm.. sold it and moved to 12-24mm i dont use tele. im experimenting with bulb flash next.. i bought a norman 200b. you want nightclub insipiration.. visit my heroes site.
http://www.ambrel.net hope this helps..