A couple of friends swear by this lightweight bouncing chair from Baby Bjorn. The springlike shape means a kid can bounce himself silly with every little squirm. It's definitely the best-looking seat I've seen; it'll let you hold off the invasion of the lime green plastic furniture for another year, at least.
For some reason, the BabySitter is frequently out of stock. Right now, Baby Age has it for $84.99, which sounds like MSRP.