[Ted S]

Corruption is something your database can always and probably will experience regardless of your setting. Increasing the number of times the database is written to either by changing options or just having more traffic/ posting/ activities means more room for things to go bad. If you do end up getting corruption it tends to be minor (although many larger vb forums have had to deal with fairly serve corruption issues) but won't be fixed by turning anything off. If you want to fix a corrupt table you can start with the "check <table name>;" and "repair <table name>;" commands from your mySQL interface.

There's a few different schools of thought on this but I like to check my main tables on a very regular basis and run the myisamchk command (another way to run check without mysql being up) nightly... but that's just me.

As for how much more intensive the #2 and #3 options are. I don't have a benchmark but it's definitely a noticeable difference, especially if you go with #3.