Best settings to use on Nikon D5000 for rave photography?

I'm planning on starting my own company, and I own a Nikon D5000. I was wondering if anyone knows the best settings, lenses (I was thinking a wide angle lens), and flash to get vibrant colors and good looking photos of people and lights.

You really can't do the job until you can make those choices for yourself. Even if someone told you the correct equipment you wouldn't know how to apply it. And, since you don't know the equipment you may take the wrong advice. You need to learn photography.

I shoot in VIP rooms in nightclubs.

I use a Nikkor 24-70 mm f/2.8 lens and a SB600 on a flash bracket and a Gary Fong flash diffuser

The angle (focal length) of a lens has nothing to do with the vibrancy or saturation of colours. Your camera is a very nice entry level model, and it sounds like it is the appropriate camera for your present level of expertise.

I don't want to put you off either photography or starting your own company, but I can't help wondering what kind of company you had in mind. If it is one where you photograph people for a living, you really must learn a lot more than you seem to know so far. For instance, photographing people with a wide angle lens induces facial distortions, and the "best settings" vary with every shot according to the light, action and intent of the photo.

Join a good club, do a training course (or better yet a degree course), read, practice and submit you photos to an honest, experienced critic. When you can answer these questions reliably for others, you should be ready to begin working with an experienced photographer (assistants often work free to gain experience and knowledge - 12 months should be enough) before striking out on your own. During that time, you should also try to do a small business training programme.