Buying or Selling: Infant, Graco Safeseat

Infant Seat or Convertible Car Seat?

Hello, I am trying to decide if I should buy an infant carseat for my newborn (due in 5.5 weeks) or a convertible car seat. I've read reviews and researched both, and I was considering a Britax Roundabout if I went with convertible, or a Graco Safeseat if I went with the infant seat. I live in a city environment so I will do more walking with the stroller vs. driving in a car (and I live close to the hospital), although my husband and I may take a few road trips (no more than 6 hours) after 3 months. We don't have any plane trips...