maximumpower
Just curious, you all use a vocoder that much in your music?
 
I love them, I just never worked them into anything.

I almost never use them for vocoding, but for cross-synthesis where one instrument modulates another (e.g., drums modulating rhythm guitar). The Pentagon vocoder works well for that.

I would say whether or not you can mix ITB with Sonar also depends on the kind of music you're producing. If it's straight ahead guitar, bass, keyboards, vocals etc with nothing in the way of "wacky" effects and sounds then Sonar includes everything you need for a great mix, no doubt about that. However if you want to get creative and/or work on contemporary electronic styles with lots of synths and wackiness, then you'd be mad not to check out what's available in the way of 3rd party tools. Even if you don't want to spend any money there are some terrific freebies out there, I always research them first though to see if anyone's having problems with them.
 
I guess over the last 2 or 3 years my biggest investments have been Komplete Ultimate, the Waves Gold bundle, Trilian and Geist. Got them all on sale at one time or another (except for Trilian) and have never regretted it. Apart from things like sound quality (which may or may not be better in 3rd party plugs), two of my favorite reasons for using 3rd party stuff are:
 
a) That they have a better interface than what's included in Sonar and I find them easier to set up - I'm always going to reach for the Waves H-Delay or Native Instruments' Replika (which was free for a while last year) because I find I can dial in the sound I want so much quicker.
 
b) That they inspire creativity, simply by virtue of being different. I know it sounds shallow but sometimes something as trivial as downloading a new plugin is enough to get my creative mind moving, even if what that plugin does could be reproduced quite easily with stock Sonar effects. What can I say? I just love new toys. But aside from that, there are so many interesting 3rd party effects out there which have been written by creative individuals who weren't bound by the usual constraints of working for a large company. I could browse the Reaktor user library all day downloading some of the weird and wacky effects and instruments that quirky individuals have created. Some of them are extremely whimsical. Sometimes they work out, sometimes they don't. But there's no denying that they fire a creative spark in me.
 
I certainly could not do without Geist. Once you've played with that baby there's no turning back.