Bumpers are a bit controversial. Some people say they are a must for protecting baby's soft spot and keeping legs and arms from getting caught in the slats of the crib. But you should never use pillow-like bumpers which increase the risk of SIDS. A breathable bumper might be the choice for you. We found a couple:
Breathable Baby Cribshield is available at Target. It has soft, see-through mesh panels, and comes in a variety of colors. It also won the iParenting Media Award, and a percentage of every sale goes to First Candle/SIDS Alliance.
Another alternative is the Trend Lab Breathable Bumper. This allows for the same air flow and visibility.
If you want to learn more about preventing SIDS, check out the First Candle website.