39 year old Unix Systems Admin contractor - Use mine everyday - goes everywhere with me for work.
Have the usual MS Office/Skype etc - but the fact I can run multiple Virtual Machines (use VMware Fusion) I have 3 x Redhat Linux VM's configured in a Veritas Cluster - with shared storage.
Also carry all my notes/research with me.
Goes on holidays (along with iPad) and use it with a 1TB USB Portable drive for storing photos/videos.
In my house - everything is now Apple - just because the last thing I want to do after coming home - is spend hours fixing a broken PC/Windows machine ........
Even my 9 year old daughter now has my old MBP as her machine - quite happily uses the PC's at school - and then swaps to the Mac with no problems.
Even bought a 13" MBP for my in-laws - as trying to remotely fix their PC/patch etc was too time consuming. They think it's tee best thing since sliced bread - and Skype with my wife/daughter - rather than expensive phone calls.
As I say to any of my friends who ask what computer they should get - "Buy a mac" -
When they then grumble saying their more expensive than XYZ Laptop.
I say - "But they just work ......."
Out of 6 family friends with kids - 4 are now running macs as well !!!

Imac 2011 27" I7 256SSD 16GB Ram

MBP 2011 15" I7 256SSD 8GB Ram

MBA 2010 11" C2D 128SSD 4GB Ram

MBP 2008 15" 2.53Ghz 2x128SSD(aftermarket) 4GB Ram (My old Laptop now given to my daughter)

Mac Mini 2010 C2D - 64GB SSD4GB Ram (CCTV system for house/gardens)

Iphone 4G 32GB

Ipad2 64Gb Ram
* ReadyNas NV+ - 4 x 2TB (5.4TB usuable)