adeskbar, for fun and profit
I have used wbar in Openbox setups off and on for the past year or so, since I saw it at work with Tiny Core Linux. I figured, if wbar is lightweight enough to be used on ultra-ultra-ultra-lightweight distros, then it is probably speedy enough for my day-to-day Openbox arrangements. adeskbar is probably equally light (the source code package undercuts wbar by about 175Kb roughly, but that’s not a guarantee it’s “lighter” ), and approaches the same issue from a slightly different angle.
If you’re GUI-oriented anyway, adeskbar might be a winner for being quicker on the configuration. Right-click anywhere on the bar itself and you get the Preferences menu, and the options there are very self-explanatory. (To be fair, you can get the same ease-of-setup with wbar, by installing a sidecar application called wbarconf.)