Here's a thread I started when I got my mac a few months back that I recommend you take a gander at. It really helped me out.
http://forum.calgarypuck.com/showthr...ighlight=apple
- VLC for a media player is a must ... it seems to play pretty much everything.
- quicksilver is a handy launcher, but it can get quite deep if you want it to
- While it costs money, iwork is an excellent office suite and I recommend you at least try the 30 day trial. They are in the process of upgrading it but I believe you can still try it out.
- If you find things get a little cluttered with windows everywhere, give spaces a try (set it up from your system preferences). It's something that is included in your mac but not everybody uses. It helped me quite a bit.
- If you are an itunes user I recommend going to the itunes store and subscribing to the Apple Quick Tips podcast. It has loads of "oh i didn't know that" kind of movies.
There used to be the general idea that you didn't need anti-virus software on a mac, but recently it's been recommended. Unfortunately i haven't dug too deep into this yet so i can't offer my impressions on anything.
Enjoy!