More information would prove useful to answering your question.
For word processing, calendaring, spreadsheet work, Microsoft Office is the
standard. That said, there are alternatives that are compatible therewith, some of which are free (Open Office, for example--just make sure you save the doc as Office-compatible!).
iLife will likely take care of most of your photography, music and home video needs.
What else are you looking to do with this machine?
Are you into recording your own music? iLife includes Garage Band, which is passable as an audio/MIDI recording platform for the casual user, but there are plenty of other options out there that are vastly more powerful. I recommend getting (at least) an el-cheapo USB-equipped keyboard/controller, as pointing and clicking takes the creativity straight out of the equation for most users (though, I must confess, there are times when I'm composing a drum track that I rely on this method).
Are you into games? What sort? My personal favorite is the FPS (first person shooter) type, as typified by the Unreal series, the Doom series, the Medal of Honor series, the Call of Duty series, and the Quake series. If you're more into strategy games there are a host of options, but I'm not the best person to ask, as I find these games most frustrating. If you're into role-playing (Dungeons and Dragons kinds of things) there are a host of titles available as well, but, again, this isn't my cup of tea. I'd recommend a visit to Inside Mac Games
for the latest in gaming news on the Mac.
Just let us know what kinds of things you're wanting to do, and we'll be forthcoming with more options than at which you can shake a stick.