"i have always used vista but i know that linux is actually programmable so i would like to change to that. can someone tell me the main differences?"
There are really too many differences to list. It's better if you try it out yourself. The best thing is that it's free, and there are easy non-committal ways to install it:
http://www.psychocats.net/ubuntu/virtualbox (virtualized)
http://www.psychocats.net/ubuntu/wubi (dual-boot)
Whatever you do, do not install it over Vista or install a dual-boot without Wubi.
Virtualization is a great option, and a Wubi dual-boot can be removed just like uninstalling any regular Windows program.
"some of the main things i would like to know is if you have a recent game (all seem to require vista) is there an easy way to play it on linux?"
No. That's why you'd virtualize or dual-boot, so you can keep Vista for gaming.
"is comparing vista to linux the same as comparing internet explorer to firefox? (in the sense of basically the same but firefox has useful addons)"
Sort of. Right now, it's more like IE and Firefox from 2003 or 2004, back when a significant portion of websites did not support Firefox. Now that Firefox is 30% of the browser market, webmasters would be morons not to make their websites Firefox-compatible. Non-server Linux isn't anywhere near 30%, though, so some peripheral hardware and commercial software support isn't there yet.
"what are the good benefits of running linux over vista?"
Freedom. Centralized package management. Easy customization.
"do you need to know an extreme amount about computer programming to be able to customize linux?"
No. I've been using Linux for years and I don't know anything about programming.
"are there many viruses out there for linux?"
No. And if there were new ones that appeared, having antivirus installed wouldn't stop them. For more details, read this:
http://www.psychocats.net/ubuntu/security
"oh and i just found out that there are different versions of linux... which is best?"
Best is a matter of opinion. A good one to start with is Linux Mint. It's based on Ubuntu but comes with popular proprietary codecs (Flash, MP3, etc.) preinstalled. After you get comfortable with Mint, you can explore some other options (vanilla Ubuntu, PCLinuxOS, Fedora, Mandriva, Sabayon, Mepis).