t depends on what you want to do with the computer. If you're just thinking of normal home use - surfing the net, writing the occasional letter, kids' homework, etc - then there's not much difference between Windows or Linux. Most distros of Linux come with the Firefox browser (in my opinion, still the best) and OpenOffice (a freeware equivalent to MS Office) along with plenty of other freebies. There are also many multimedia players available free for Linux that are every bit as good as anything you can get for Windows.
However, if you like playing games then Windows is probably the better choice as there are far more games available than for Linux. Some Windows programs can be run under Linux using a program called WINE, but many don't work.
Linux is also inherently safer from viruses etc because of its permissions protocols. Some people find those a pain in the butt, but they are a good security feature and not really that much of a hassle once you get used to using them.
I do a lot of webpage coding using php and mySQL and that's easier on Linux. Once they're installed (that's a doddle), you can just use them. You don't have to run any other packages such as XAMP or JSAS each time you want to do anything.
Another reason I prefer Linux is that it's quicker on my PC than 7 was and I'm not forever having to re-boot.