Personally, I think you've got the military tactical pretty much covered, so the Commander would be out. So you're left with the Sebenza and the SpeedTech.
First off, it sounds like ultimately, you're going to be buying both. You've displayed excellent income disposal skills up till now, and there's no reason to believe that you won't get better and better at feeding your habit once you've tasted the sweetness which is Sebenza or Synergy. So it's not a question of which, but rather which first.
They're both excellent knives. You will be well served and well pleased by either - and especially both.
Based on what you've got now, I'm going to guess that a tiny blade will leave you sort of flat, so if you go Sebenza, go large Sebenza. The Synergy blade is plenty meaty.
What it sounds like you need is some color - something with style. The Synergy has you covered there, being one of the sexiest, most colorful knives out there. Depending on your needs, you can go relatively subdued, or let it all hang with the California Camo. Phenomenally comfortable handle.
The Sebenza has color and flash available, but you'll pay quite dearly for it. If quiet style is your thing, though, the plain Sebenza is smooth and classy.
[I stand corrected] Both knives have pocket clips.
My purely personal preference is the Synergy, but either way, you're getting an exceptional knife - worth every penny. Try to handle the knives before you buy - the knives feel quite different, from each other and from what you've already got. I would bet that you'll really like one over the other once they're in your hand.
I think that the Synergy or the Sebenza will be an excellent addition to the selection you've got going.
You really will be buying both, though.
[This message has been edited by Brian_Turner (edited 01-25-2000).]