I have the Cortina travel system, I like it and use the stroller often when I go shopping. I have a jogging stroller, not the Bob, but similar, and have just started using it. I love how lightweight it is and how easy it is to push around. Plus, it's much better to take to town lake as well as for walks around the neighborhood.
As for the folding aspect, I find that the jogging stoller actually fits into my SUV better than the Cortina, that one's a hassle to pick up and try to maneuver in the back. My recommendation is to get a carseat with the stroller frame, it's smaller and easier to use, and then get a jogging stroller to use when the baby is 6 months old. I did see a set up with the Bob where you could connect your carseat in, you may want to check that out as well if you're interested in saving money by only going with one stroller.
Also, as a side note, the Cortina carseat doesn't fit really well into most shopping carts, so it's a pain in that sense as well. And in the stroller, you are unable to use the storage basket for shopping bags when you have the carseat in it, so you have to get one of those "Mommy Hooks" for everything.
Finally, if you are planning on getting an umbrella stroller for later use, don't get the Combi, I have it and really hate it, a total waste of $100. A good swing (major necessity) is the Fisher Price rainforest that goes both ways and plugs in. That way, you don't have to change out the batteries every week. Hope this helps!