While many of the answers below are correct, they don't boil things down clearly, IMHO. This site does, and the main point: InnoDB is row-level locking, MyISAM is table-level locking. This means, generally speaking, MyISAM will be better for OLAP (analytics, mostly reads) and InnoDB will be better for OLTP (transactions, mostly writes, or at least many writes).

Wow! A nice linguistics answer thrown in with an excellent description of handling encoding! Thanks, Solomon!