There's no reason to give up running just because you had a baby. Bring him along! The BOB Revolution Stroller ($449) can be used once your baby is 8 weeks old, and he can ride until he's 70 pounds, so it's well worth the investment.
The front wheel swivels, so it has amazing maneuverability, but you can also lock it forward for increased stability if the terrain is rough. The suspension system offers a smooth ride for your little one, and pushing it is a breeze. Your guy or gal will love zooming through the neighborhood, watching all the people, trees, and cars go by. It's a great way to get you both some fresh air, and if your baby is having a bad day, a run in the BOB is sure to have a calming effect. Since the seat can recline, your peanut may even nap! If you have two children, pick up the double stroller ($659).
Jog or walk on a sidewalk, paved bike path, or dirt road, and I've even taken it on a well-trodden woods trail. I also bought the weather shield ($59) to protect my daughter from drizzles, wind, and cold. I feel good knowing she's comfortable and safe, and it allows me to get my runs in while still spending time together.