Well, I started with a Halo G6 and if you do go that route, it's a decent cig-a-like. But if you already have a V2, then I wouldn't bother.
The Triton is ok, but it does have a somewhat proprietary threading on their tanks and batteries, so you wouldn't be able to use other tanks on the batteries, or the Triton tanks with regular 510 threaded eGo batteries.
I'd go with a small eGo setup with 510 threading. You can always still use your cartos with your V2 and Greensmoke alongside with whichever eGo system you get. Just because you are "upgrading" doesn't mean you still can't use your older equipment as well, right?
The Mig-Cigs are gaining a lot of traction right now, but seriously, an eGo battery with an iClear 16 would produce a lot more vapor, last longer, and is actually smaller (shorter) once assembled. My first pick for you is still the
Ego Mini Starter Set - 2 Complete E Cigs - Only $35.00!! Or, if you can spend a little more, get this:
Vision Spinner VV battery - [No CN/UK airmail][2013 NEW] Vision Spinner Mini 400mAh eGo Variable Voltage Battery Get two iClear 16 tanks, a pack of replacement heads, and a charger. Altogether should cost you about $55 plus shipping.
Feel free to keep asking questions!