Not much to say about this. I've been using Cakewalk Windows-based sequencers and audio recorders for 15 years. Upgraded with goodies and new features almost every year, never begrudged the upgrade tax. SONAR 8 is pretty much perfect. Check out the user forum, it's an excellent resource.
Update: SONAR still exists in 2019, but it has a new owner, and a new name: Cakewalk By Bandlab. And it is FREE. You will not find better value for your money, this is a professional, mature, music production environment.
Dimension Pro was Cakewalk's flagship virtual synthesizer for a few years, at least until Rapture came out*. Dimension LE was bundled with SONAR 7, but I didn't really use it seriously until the "pro" version was bundled with the SONAR 8 Producer upgrade. It included an impressive sound library, particularly some wonderful string section patches which I've started to use.
* Now Rapture LE is bundled with SONAR 8.5. I detect a trend.