They Type of stroller you want will depend on what you want to use it for...will you keep to home and go for long walks with it, are you a jogger, do you want a lightweight/compact one for short shopping trips/travel destinations??? You may need more than one for different purposes.
We live in a very small town with BAD sidewalks, so I wanted one easy to push on our long walks, and with real air-filled tires for easier ride for the kids....good shades and reclining seats were importnat to me too....
I got the Baby Jogger City Classic for a great deal on Amazon. Like this, but last years colors of Navy and silver: http://babyjogger.com/city_classic_dbl_dtl.aspx
Normally, they are about $600 for the double, new, but i got mine for about $370 it was new, but was the last year model, so discounted, and free shipping on Amazon!!!
It glides like a dream and turns on a dime, reclines independantly and has independant canopies and they are great shades that come WAY down. It will hold both kids till they are 50 lbs each. It also has a "suspension", so handle all the bumps and stuff we go over out here. A few negatives, it is large when folded, and doesn't have a latch to keep it in the folded state, and weighs 35 pounds empty. We have only 2 kids and a minivan, so although large, we do stil take it on trips with us.
Originally I had had a Jeep stroller, where the kids sat one in front of the other, and it was just as heavy, a little less bulky when folded, but VERY hard to steer and rough for the kids on uneven terrain here. I took it to my moms house and left it there, so when I am going to my hometown, I know we don't HAVE to take a stroller. That one we got secondhand, so only $60.
I am thinking about getting the lightweight Jeep or Graco double umbrella style stroller, too.... we will see, it would definitely be easier for travel.
While the baby was little, and even now, sometimes, it is easier when shopping to just get the cart that has the baby seat atttached on top, or to put the big girl in the cart and the baby in a carrier - like a BJORN or a sling.
Good Luck!!!
Jessie