Well, I have a masters degree, and I am trying to get a PHD.  I think when thinking about synths and how best to use them, you have to break them down into their various categories.  So you have subtractive synths, these are the easiest to master and once you have a good grounding in subtractive synthesis it becomes easier to master the rest.  The Z3TA is a subtractive synth but it has a lot extra features, so I would suggest a Moog emulation to start with because it's a basic subtractive synth and if you think about how many classic recordings it's been featured on it's really all you need if you are a band looking for a synth sound.
 
The next category of synthesis is wavetable, the most famous wavetable synth is the prophet 5.  This synth is pretty much the same as subtractive synthesis, the difference is rather than using an analogue oscillator to generate your sine wave or square wave, it uses a very small sample called a wavetable.  Rapture is an example of wavetable synthesis, again though it is a very complex version of it.  The 80's synth sound, is made up of wavetable synthesis.
 
The next form of synthesis is digital, and again it is a huge part of that 80's sound.  The most famous synth of that era is the DX7.  This time instead of a oscillator or wavetable to generate your sound, it uses DSP or digital signal processing.  Cakewalk don't have a digital synth.  It also is harder to use and get a usable sound out of.  So if you are a beginner steer clear.
 
Next is additive synthesis, as name suggests its the opposite of subtractive.  Again it's harder to use than wavetable and subtractive.  And it's not very common.  I've only used one a few times. 
 
Then there is granular which use a very small sample, a grain to create it's sound.  At the moment there are very few of these in VST form, Cubase have just released one called Padshop.  I've used it but it's quite difficult to get a sound out of.  But its good for soundscapes.  If you like King Crimson, Fripp uses one albeit hooked into a guitar synth to create funnily enough his Soundscapes off a lot his 90's work and beyond.  Again avoid if you are a beginner.
 
Finally there are rompler style synths.  These are similar to wavetable but have less control over their actual sample but tend to have synth controls.  Dimension Pro is an example of this style of synth.
 
There are of course modular synths too, but avoid unless you really want to get a PHD.  I've used these and have built a few, basically depending on what brand you are using you could make any type of the above synth using a modular.
 
And there are of course instruments like the Mellotron which is really a rompler, not in its hardware form but def in its virtual form.
 
I think that covers synthesis.
 
Ben             

Anderton
+1 on Rapture. I loved it when it first came out and still do. Almost all my projects use it in some capacity.
 
I did a comparison of the Rapture "Minimoog filter sound" with the Arturia Minimoog on Harmony Central, and no one could tell the difference. So I even use it for VA-type applications.

+1 on Rapture, too. BTW, Craig, is there any chance of having a Rapture 2 sooner or later?

Another vote for Rapture here. I've just finished a job tonight for a TV client, 3 bits of electronic background music, and I've used Rapture on all of them (8 instances in one case).
 
z3ta+2 is totally worth the money, though, it should be said. Superb synth, and widely used outside of the Sonar community.

ah!  lots more info and more interesting synths to look at! kewl...
 
I remember ducking around with some modular synth a long time ago...  since I had no pressure to create anything particular at the time, I took it as a game and it was a blast!  But yeah, I went away for a long while, and I gather from your words, that I won't get away with just using one and probably can't even stop at 2 or 3  ;-)
 
Will just have to stop worrying about the time I'll spend on the learning curve, since I'll have lots of time sitting around in a rainforest through the monsoon season!  My last laptop housed an ant colony twice, and it still lives (EMF seems to be like disco music to ants, they go wild. After I chased them from the laptop, they moved into the wireless router instead!)...  hopefully, the new computer will prove equally resilient.

I have such a hard time figuring out what your preferences are, and your level of knowledge!
Perhaps it would be helpful for yourself to try to be specific? For instance, you have said you don't really have a sound preference, and indicated you have used samples in the past. Yet do you expect a "synth" to have piano sounds, drum kits, hammond organs, string orchestra's? Many sample based soft synths offer this, but none of the (virtual) analogs we have been talking about do. Probably you'll end up having a few synths for different needs, but so far you have refused to pick any direction at all, haha :)

As for learning the interfaces, because you mentioned they were complicated and want a nice inviting interface for programming, I suggested a hardware analog to learn synthesis on. And now it seems you owned a hardware Korg analog before I was even born, and had a modular synth??
I'm getting super confused here!

Although Zeta+2 is my go to synth, I find Pentagon to be the easiest to program.  Having every control always visible helps in that regard, imho.

If you can't make a song with DimPro, Rapture, AND Z3ta2 then you need to hang it up and get a gig wearing a paper hat and saying "do you want fries with that"! DimPro and Rapture already come WITH SONAR, and are each in their own amazing. Z3ta2? Absolutely amazing. Especially if you scooped it up for the $40 or whatever when they ran that deal.