How big is your trunk? What specifically do you see yourself using it for? Inside, outside, sidewalks only, grass, trails, etc?
Personally, I would wait on buying a stroller until after you've had the twins and get the double snap n go for now (and compatible car seats). Having twins is HARD, much harder than one can even imagine unless you've actually gone through it. The double snap n go will get you by (it's fine for grocery stores, malls, drs appts, and smooth sidewalks) for at least the first 6 months...probably even a year if you don't have huge babies. It enables you to transfer babies from car to stroller without waking them (trust me, this is NICE). It really gives you time to get a feel for what kind of stroller you'd like to have based on your new lifestyle with infant twins
The price of the double snap n go (and you can get one used for half price on craigslist) is, in my opinion, worth paying in order to really figure out what stroller would best meet your needs so you don't fall into the trap of buying multiple strollers. Especially if you're really wanting THE ONE
The only reason I can see to recommend against a double snap n go to begin with is if you live in the city and must WALK everywhere...then you probably need a good all-terrain stroller.
Having said all that, the Baby Jogger city series double strollers are very popular on this board. The Mini double, which is impressively lightweight for a double if you plan to use it mostly for indoors or smooth sidewalks. The City Classic or Elite if you need an all-terrain (i.e. you go walking on bumpy sidewalks, dirt trails, etc.) or if your twins are larger (this is the other reason to wait...if you have really tall kids you have to take that into consideration when buying a stroller).
So it really all depends! But I would really encourage you to wait so that you can try out strollers in person with your twins, and so that you can further evaluate what kind of stroller you need if it will be THE ONE. Hope that helps!!