We have a Maclaren side-by-side double stroller and have loved it. Each side adjusts independently, and can lay flat for the baby. When our second son was born, our oldest was right at 2.5, and it was perfect. With our third son, our middle son was 3, and I ended up wearing the baby more than using the stroller. However, there were quite a few time where I used the side-by-side for the two BIG boys and wore the baby! I do like the ability to buckle up both of the children in the stroller and know they're not going anywhere. It's quite a bit of peace of mind, especially when you're juggling with more than one.
Maclarens are excellent quality - we now have three different Mac strollers of different styles, for different uses. You may be able to get a good deal on them on Craigslist, too.
Hope this helps,
H. B.