First of all dq22, welcome to Mac ownership and welcome to MacRumors. Please ignore any of the above posts that are critical or negative as we are glad you are here and hope that MR can be a source of support for you.
As far as what to do on your new machine, well, with the software already installed (OSX + iLife) you can do web surfing (Safari), email (Mail), video/audio conferencing, (iChat), music (iTunes & GarageBand), photo management and basic editing (iPhoto), video editing etc. (iMovie & iDVD) basic website creation (iWeb), contacts (Address Book), calender management (iCal), and system back up (Time Machine).
There are tons of other built-ins that are a part of OSX and of course there are numerous free and availble for purchase applications that you can buy. I'd suggest looking at what you want to do with your computer (money management, graphics, video/photo, music, etc.) and then search these forums for people's suggestions regarding programs of that type/genre. MRoogle is a great search tool that will help you find posts here on MacRumors.
I hope that helps.