My first and second child were 2 years and 4 months apart, and I loved my MacLaren twin traveler. It probably has a new name by now, but it's a side-by-side double. Both seats recline fully, have independent sun shades and can hold up to 45 lbs each. It's expensive, but since my first refused to walk anywhere when the 2nd was born, I would have practically been housebound without that stroller. I travelled frequently with the kids (without my husband), and the stroller handled airports, taxis and cranky kids beautifully. We did Sea World and the State Fair with that stroller when they were 2 and 4 years old. My kids are big, so the high weight limit and easy steering were really essential for me.
Try to borrow a few kinds to test drive before you buy. Moms at playgrounds are often happy to talk about their strollers, and let you drive it around a bit. It's important to get kids sitting in it when you test drive it. Remember that adding 50 lbs of kid makes a BIG difference in how the stroller handles, and that's not including all the gear you schlepp when you're at the zoo with a toddler and a baby!
Good luck, and happy shopping.
S.
SAHM of 3