If you are a runner, a baby jogger is a GREAT investment. We also purchased a Graco "Travel System" that had the combo baby seat, stroller, bases for the car.

If I had to do it all over again I would:
1) Buy the Baby Jogger with the car seat attachment bar
2) NOT buy the travel system and get a good, compact, light-weight, yet durable stroller instead.

The very few times we needed the stroller with the car seat holder, we could have used the jogger if we needed to. Relatively speaking, your baby is in that infant car seat for a short time. That heavy, awkward, "travel-system" stroller got used all of 2-3 times and now we can't sell it. We exclusively use the Jeep stroller and jogger. The downside is that the baby has to be able to sit up before they can ride in something like the Jeep brand stroller. But babies are usually sitting up at 5 months of age anyways.

A fixed front wheel is a must, especially if you are using it off-road.

We've had our Baby Jogger for 6 years. I can't even tell you how many miles are on it. I trained for the Chicago marathon in 2006 pushing DD in that Jogger. And then she came with me to running club all winter long. Now DS rides in it while DD bikes and I run. It has been well worth the investment. I know it's expensive, but it is the one baby item I am glad we "splurged" on.