D.M.
Congratulations on the upcoming arrival of your son! Our daughter was 17 mos when our son was born. We bought a double stoller - Graco. It's a nice stroller and the kids were comfy. HOWEVER it was 40 lbs w/o the kids in it and almost 80 with them. I hardly ever used it so it was a waste of money for us. It was much easer to put the baby in a sling/carrier and the toddler in a stoller or cart. I'd try that first and if you find you need to get a stoller, go for the lighter weight ones (not quite as sturdy, but easier to manage) - OR the sit and stand ones. Good luck.