Portraits, band promos, landscapes, live music. General all arounder

Dont hesitate, go for nikon D7000, its much much better than D300s for much lower price. You will get good high iso performance, better image quality and a lighter camera. So if your worries are all about noises, D7000 will handle the job perfectly for you. But if you are worried about sharpness, then changing bodies or lenses might not be a help for you; since you as the photographer play an important role in getting sharp images, I can provide you with hundreds of images taken with D3100 that are sharp and have good image quality. So as a friend I also advice you to study more about how your camera works and what is its limits and how you can tweak it to get the most out of it. Anyhow I wish you luck on your future career. 

I've got the d7000 and im really happy with it. 39 focuspoints are more than enough! The low light performance of D7000 is said to be better than of the D300s, the handling combines many entry-level features (Dial with shooting-modes) with some features of the "pro-Line" (Dial with shutter-mode). The body feels very tough and relyable.

Nikon also improved the RGB-Sensor. (D300s: 1.005 pxl, D7000 2.016pxl).

One thing may be interesting for you: There are rumours that nikon will release a D600 (FX), which seems to be a FX-Sensor in a D7000. Price is said to be 1500$ maybe lower. Release-Date: shortly before Photokina in Sept 2012.

www.nikonrumors.com

some pictures i've taken with D7000 (17.12.2011 and younger, i took the "older" ones with my "granny" D70s):

http://wuerzburg.nightfever-online.de/?i=248/