Here are some links to other sites taht offer good, cheap or even free music software for PC

REAPER is a multi-track audio recorder and VST host.  It's very reasonably priced and updated every week (sometimes more).

Synth 1 is not only one of the best free VST instruments available, but also one of the most popular.  Download it and find out why.

Big Tick Software has a few free synths available for download on their site.

Smart Electronix is a group of developers who have designed some truly remarkable plugins - check 'em out.

For more info and links to other great software, check out KVR, a site dedicated to making music on computers.  There's a database of software there and a very active forum.  It's probably the best place on the web for up-to-date info about music software.