Finding great software for your Mac can sometimes feel like a gamble. But we’re here to help—each month in Macworld and every week in the Mac Gems Weblog, we deal out low-cost software that delivers big-time returns. We call these programs Mac Gems, and as we approach the discovery of our 500th gem, it seems appropriate to show off our aces—the very best low-cost Mac software. We’re including the 17 gems that have received arating, as well as apps with a rating of or that deserve special recognition. So don’t fold your hand—we’ve got some sure bets for you.