Ask HN: Which plan should I offer as my free trial

Currently my SAAS App BugMuncher has one plan ($19 / Month), but I'm soon to be launching two more plans (http://bugmuncher.com/pricing.html - although the details and prices on that page aren't exactly what I'll be offering) I was wondering what plan I should put people on when they start a free trial? My first thought was to put them on the top plan, to sort of give them a taste of everything BugMuncher has to offer, but I've noticed quite a few SAAS apps put people on the middle plan for a trial.