I use dual boot with win7 and OpenSuse 12.2. I must say I rarely boot into windows. It's worth pointing out that if you're a gamer Steam is in a beta stage for use with ubuntu. I have tried Linux in its many different forms. OpenSuse only gives me a headache when i need to do networking stuff. Even then its just a case of switching off the firewall.
Stuff you get free of charge with Linux:- Libre office(or similar), k3b(cd burner), video editor, gnucash(finance thingy). GIMP(like Adobe photoshop)
I know you can by other means get stuff for windows for free, but when you install Linux you get most of the above installed and ready to use.
I also like the way Linux partitions the drive into OS/Swap/Data makes upgrading and backups easier. It does have it's problems but it's FREE! I tend to use Ubuntu 12.04 to breathe new life into old machines, quick and 9 times out of 10 i'm not looking for a driver that no longer exists(generally sound card) for days.
Nearly everyone now a days can operate on a cross platform basis. Everyone recognises the Firefox and Thunderbird icons and the thing that looks like a power button in both Gnome Destop and KDE Desktop is you guessed it the off button. The online help via forums is amazing to.
Basically I put opensuse on my Dads machine and told him it was a new Desktop theme and he's found his way round and he's not massively computer savie .