Again congratulations.
Regarding MS software I am afraid that I have to own up to buying the most basic MS Office, I needed it so my children could do their homework. In my defence though I have just recently bought iWork '06 but haven't yet had a chance to play with "Pages2" or "Keynote". My MacBook does have the dual core intel "chip" but have yet to go through the process of partitoning the hard drive and installing "bootcamp" and MS XP SP2. I actually only have one programme that I really need that will only run in MS.
Otherwise I tend to stick to Apple proprietry software, so I use Safari for my browser although others rave about Firefox, I also use the basic Mail programme, but I know others swear by other programmes.
The only other software I add is VLC to play DVDs. Although a bit "clunky" this programme will solve the problem you may have after you have changed region on your DVD player too many times. I also install Windows Media Player to play those ineviatable .wmv files that people send out. To stream the BBC you will need Real Player which is easiest to get from their website, rather than following the BBCs links.
Additionally for the kids I have MSN messenger for Macs, and of course no computer would be complete without Skype for those free calls!
Regarding tips and tricks, I tend to buy Mac mags when I travel and look through them. This site is also a good source there are a number of very qualified contributers. The Mac website>support>discussions can often help, failing that just call your local Mac support number. Here is a little trick I learnt, if you have to make three calls on one problem you will be transferred to a level 2 technician, with no disrespect intended to some level 1 technicians, but level 2 technicians are generally fluent English speakers and will solve your problem. I discovered this after a level 1 technician had me do things that caused me endless subsequent problems and then took forever to undo!
Other things that will make your life easier; learn the keyboard shortcuts! All those Apple+function that appear next to the command from the drop down menu (like Apple+P=print, Apple+C=copy etc).
I also like to customise my Mac(s). Most applications can be personalised by clicking on the application header in the toolbar>preferences and then take it from there. For example you are probably reading this in Safari so try Safari>block pop up windows (Apple+K), try Safari>preferences> and from the menu>tabs>enable tabbed browsing.
One I would recommend you check urgently is your Firewall. You find this from System Preferences (Probably an icon in your dock)>Sharing>Firewall, and make sure that Firewall is ON.
Personally I have no anti-virus software and I have never read anything good about Norton. I did have it installed on my first Mac and it then caused me problems without ever doing anything useful! I feel similarly about AOL by the way.
If your finances stretch to it I find a .Mac account a good thing but at $100 pa it is a little pricey.
I am sure if you ask specific questions you will find people more than willing to help, but that should be enough to be going on with.