SO, my wife's mac is really getting pokey and I thought before turning to my trusty old side kick Cocktail + Zap PRAM I'd ask you guys what you're using now a days to keep your mac running at tip-top speed and performance.

Her rig is a 3-year old ibook, she's a writer so she really only uses 3 apps, Word, Entourage & Firefox. So there's not many files on it filling up the hard drive (as opposed to my G5 with 3 extra drives.)

SO, what's your preferred method/software?

I love cocktail! You could also create a new user for her, transfer her documents over, etc. sometimes (depending on how many applications you're installing) pref files get messed up and creating a new account sweeps it all out.