I don't have twins, but I do have two that need to still ride in a stroller.
I LOVE my Bob Revolution Duallie. Not sure why the other Mom said it didn't fit through doors, I don't have any problems with it as it fits through most single doors and I can usually steer it through with one hand. Occasionally I bump sides, but it does fit.
Like another Mom also suggested, she should buy a stroller that she will absolutely love for the next 3-4 years and that fits her family's lifestyle.
For us the regular double strollers just wouldn't cut it. We originally had a Graco DuoGlider that I got used. HATED IT! The wheels always got stuck in the concrete cracks.
But since we are an active, outdoorsy type of family, the Bob is awesome! Those wheels ride over everything. We have taken it to the beach a lot and with a little extra effort it rolls over the sand. So we just pile everything onto the BOB and the kids walk onto the beach (they are 1 and 3). We have taken it camping and I use it as my everyday stroller.
True, it is quite expensive and kind of heavy. But I didn't find it any heavier to left than the Graco Duo Glider. And given that it folds in half and you pick it up in the middle, it makes it easier for me to hoist into the car (we have a minivan). I have also used it in a Highlander and my sisters small Mazda 6 and our Camry.
We bought ours at REI.com and had them free ship it to our local store. Usually around January, Labor Day and Memorial Day they have the Bobs on sale for 20% off. The Duallies usually run about $525, we got ours for $104 off the regular price.
My good friend has most of the double strollers mentioned here. She thought they were okay. THEN she drove her two kids in my Duallie and fell in love! Now with Baby #3, a 3 yo, and a 4 yo, she is thinking of getting it too.
I would also go to a place like USA Baby and test drive all the different strollers before deciding. I did that and decided on the Bob.
Also another good thing about the Bob, is the lifetime guarantee. I have had a few of the screws fall off and I called the 800 number and they sent out the replacement parts right away at no charge. And the customer service people were really efficient and very nice.
Good Luck!