If you received a new Mac for Christmas, or have been using a Mac for a while now, MacLife Magazine has a feature entitled Setting Up Your New Mac: The First 25 Things You Need To Do. It offers some good advice and seasoned users may wish to visit it as well to check out iPhoto Library Manager and AppTrap.
As well, is anyone using Yoono to simplify their online social life? (Thanks Shane M)
Finally there is also PunyPNG where you can compress image files.
Oh yeah, and all are free.