if i start getting mods whats the chance of corrupt data and stuff

Very small, if you have a decent anti-virus on your computer.
I've been downloading mods for many years and I don't think I have ever had any real problems with them.

i also have been downloading mods now for 5 or so years and not one virus. i do though tend to stick to the sites with the best reps . im a bit leery sometimes of just randomly downloading from a modders site that isnt well known . anyway please do not let our statements convence you its always safe all the time. but thats where the good antivirus pluto mentioned comes in. have fun with mods.

Do you know any good mods?

http://www.mwmythicmods.com/

Ummm, yeah.
There are thousands of mods, and hundreds of great ones.

http://www.gamesas.com/index.php?/topic/1060141-mod-recommendations-for-new-players/page__p__15392814__fromsearch__1&#entry15392814

The main host of mods is http://planetelderscrolls.gamespy.com/View.php?view=Mods.List&game=3, where you can view mods by category or popularity.