There are a host of programs out there for users of Mac OS X which I thought I'd mention as being especially helpful to me these days. For simplicity's sake, I'll just comment on only a few, since most people probably only want to check out a few from time to time, not a whole slew of them.
* iPhoto Buddy: helps you gather multiple iPhoto Libraries in one place; you can see the various albums and Smart Albums in each library [donationware]. iPhoto Buddy
* WhatSize? This program measures each file and folder on a hard drive and you can show the resulting data in a number of formats [donationware]. WhatSize
