Root is giving yourself superuser access to your phone. With rooting, you can change ROMs, install apps that need superuser permission like screen shots, free wifi tether, uninstalling bloatware, and overclocking your device. There are others but those are the most common.
Many people are quick to tell you how great it is to root your phone. What about how awesome it would be without added complications. Rooting is what most people consider adding extra features to the phone. Which could be a nice thing if you're the type of person that love to explore your phone capabilities.
As usual there are always "Pros and Cons" to almost everything. Sometimes the "Con outweighs the Pros", and vice versa.
The final decision solely remains on what you're looking to get out of modifying your phone. The posted link above should give you a clearer view on what rooting is.
Note: Rooting also Void the phone warranty.
Another point in my experience is the chance to play and tinker will all the custom roms until you find one that you like and also works well with your phone.
thanks for all the answers. they were very insightful and helped clear alot of questions i had and was slightly embarrassed to ask. hopefully other noobs can read this and get better informed!