I too think AV (Approval Voting) is the best. It's bog simple to explain [ETA: and to implement using existing voting equipment], and completely immune from both strategic candidate selection and strategic voting. Its only downside, IMO, is reduced detectability of vote count tampering: there's no simple relationship between the number of voters and the number of votes, as there is with plurality voting or even IRV. So if you're going to use AV, you have to have an auditable paper trail. That's a very good idea anyway, of course, and lots of places are moving in that direction, so I don't think this is really a barrier.
(For very small numbers of voters, such as for elections within an academic society, Rating Voting is even better, but its advantages fade as the number of voters increases. AV is just the limiting case of RV with only two values.)
(For very small numbers of voters, such as for elections within an academic society, Rating Voting is even better, but its advantages fade as the number of voters increases. AV is just the limiting case of RV with only two values.)