S.T.
I used the Snap-n-Go. Bought this online. I have twins so I really wanted to something super light. Loved it. You can put your car seat (most brands-check first) right into it.
I currently use Graco side-by-side for my girls (they are 2 now) and love it. Need some more space up top for stuff, but I often go grocery shopping and put all my groceries down below. Cant quite get everything, but I can get quite a lot. It breaks down very easily as well.