Could be a bank, a restaurant, a parking lot in a busy area. I have done over 30 Craigslist transactions involving coins, and always make this a rule.
Other rules: meet during the day, dont give out your phone number unless you have to, bring a friend if possible, if anything seems out of the ordinary then walk away (trust your gut instincts), and dont give out your real name (even make sure your email address doesnt have your full first and last name - too easy for criminals these days to track you down with the internet)
Use simple common sense, and you should be fine. Buying something from Craigslist is no different than buying something from a newspaper ad, yet people get all freaked out because it's the internet.