I use a lot of software to make my music.
As you may already know, I am an avid user of SONY products which include: Acid Pro 7, Soundforge 9, Vegas Pro 8, Cinescore, and CD Architect 5. Acid and Soundforge are used on every one of my tracks for mixdown and mastering. I also use Vegas to make music videos for my tracks.
I use the SONY Batch Encoder inside Soundforge to produce MP3's and WMA's for release to sites like MySpace, Soundclick, iSound, Reverbnation, etc..
My main host program is FL Studio 8 XXL which is available from Image Line with an additional 10% off if you click the link on this page before placing your order.
VST and DX plugin's are the synthesizers and effects that produce or manipulate the sounds within the host program. I use a lot of these plugin's while creating music.
I also produce and use my own sounds which give my music a unique and very distinctive quality that says "ozone333" when you listen.
Plugin's are broken into a few categories: Commercial - which you pay for, Open Source - which are free with limitations, and Free - which are free with no limitations.
I use all types of plugin's in all three categories but the free plugin's are the ones that I use the most.
I get lots of free plugin's from many different sources. One of my favorite sources is Computer Music Magazine from the UK which is considered to be very expensive in the USA as a subscription, but in my case, a wonderful investment.
Computer Music is a great magazine for learning how to use every type of audio software on the planet for making music. Their tutorials encompass multiple pages and their expertise is like having my very own instructor available to me on a 24/7 basis. Every conceivable facet of the computer music making experience is covered in a useful and understandable writing style.
The magazine comes with a DVD packed with samples and free plugin's from major and minor software companies all over the world. The DVD also includes tutorials and DEMO's of Commercial software and plugin's. Reader Music, Master Classes, and other goodies.
More recent versions of the DVD include "The CM Studio" which is a complete software studio including tons of synthesizer and effect plugin's created by major and minor software companies and made available exclusively on the DVD FREE.
The investment of around $120 per year makes this subscription in my case well worth my money year after year.
The other source I use to find free plugin's is a well known website to music enthusiasts called KVR Audio which was recently purchased by the folks at Muse Research who make a very popular line of Hardware VST Hosts.
They list every conceivable plugin known to anyone in their huge database and provide links to download them. They also list all of the other types of plugin's as well. Their database can be searched with very specific terms leaving you with only what you're looking for, which is great when you have a huge database such as theirs.
I suggest that if you want to get into the world of making music on your computer that you spend the money on the CM subscription and log into KVR on a bi-monthly basis at the very least. These two things alone will get you going in the right direction towards computer music making.
Here is a list of the FREE plugin's that I use almost constantly in my music:
ReFX - Claw
Audjoo - Helix beta
[now a commercial synth for $149]
Muon - Tau
[no longer available]
Tweakbench - Padawan
Superwave - Superwave P8
Togu Audio Line - Bass line