The total cost of software on this system was exactly 0 dollars. The laptops were systems destined to be tossed out, and could probably be bought for a hundred dollars or so each (if that). With a bit of TLC, they're completely cleaned up and run beautifully. One system had a bad fan, but a good and thorough cleanup of the air passages in the body of the laptop ensured good airflow. When I find a replacement fan, I'll put it in, but for now it's limping along beautifully.
I spend a lot of time at work installing Windows on various kinds of fast and current systems, from servers to laptops and workstations, and I have never had a full install done in less than 4 hours. Sure, I can have a running computer with a default install in about 1.5 hours, but then I need to update EVERYTHING before I even consider connecting to the internet, install MS Office, tweak the virus and anti-spyware, and download the latest drivers for everything.
Edubuntu's install process, from power-on to the last sign-off, took less than 90 minutes. Boot, choose installation type, install, run updates, install the web filter, and done. Rock solid, stable, all drivers installed without ANY effort - this is how computer use should be... but this kind of computer use would also put me in the poorhouse.
On the one hand, I wish more people would adopt Linux, whether by using a Ubuntu-based distribution or any of the other distributions that can be found with a fairly simple search. Many of them allow the use of a live cd, which essentially runs the entire system from a CD without touching the hard drive. This is great for users who don't want to take the direct leap and would prefer to just test-run the software with the option to install alongside or replace Windows.
On the other hand... if everyone's computers just worked, I'd kind of be out of demand as the extremely skilled network admin I profess to be. Sure, there would always be a demand for people skilled with the intercommunications of computing systems, but the easy money of fixing Windows would be just a fond memory. Spyware, viruses (or virii, if you will), adware... these things MIGHT take a foothold in the world of Linux, but it's very, very unlikely. Linux is incredibly secure, and the core of the OS is kept very well separated from the idiocy of end users.
Give it a shot, download a CD, burn it, boot it. There are forums all over the place for support, and the communities are incredible. Good luck!