Welcome to RCNT!
This site is a good place to get started.
vbgagnon has offered up some good questions that can help steer you in the right direction.
Here are some others:
1. Do you have a local hobby store nearby?
2. If so, what kind of stuff do they stock regularly? That will help you decide what you can get your hands on the quickest.
3. Do you have any issues shopping on line? If not, then your options just got larger in variety.
4. If you want to become a racer, is there a track nearby? Is it a ROAR only track? You will need info from the LHS on this one.
5. Are you financially free or limited?
6. If a basher is what you want to be, all terrain, off road, or a mix of on road and off...you'll have to decide. Monster Trucks are the king kong of bashing. They can go almost anywhere and handle almost anything...and can move pretty quickly. Buggies are the off road rockets combined with the strength of a tank; however their ride height limits their all terrain capability. Stadium trucks and on roads are not much fun in the all terrain/off road environment, but can be enjoyable.
7. Are you mechanically inclined or inept? If you can't turn a wrench to save your life, either now is a good time to learn or you will want to stick with Ready to run models or electrics which are a little easier to maintain than nitro RCs.