I think what you have to ask yourself is this, what, in the real world, really interests you. Usually, I find that what we love in the Full Scale world, usually takes shape, on a smaller scale, in our Radio Control Collection. Nowadays, the choices available in all disciplines of the hobby /sport, compared to when my father and I first started going to Snoopy's, out in Randfontein during the early 80's, is too much to write down in this post. Suffice to say, if it exists in the real world, it will be available somewhere in a hobby shop. Either in Kit Form or Ready to Go.
So, if you enjoy the World Rally Scene or Formula one grabs you, then there is a model waiting for you NOW at your local hobby shop. Same goes for Boats. Now I have read some prior posts that Cars are boring. Yes, for them it most probably was extremely boring, but their could be a number of reasons, like lack of places to run the cars or lack of friends to race with. But if you see some of the die hard RC car enthusiasts at a race meeting, then you will quickly realise that they, are far from bored. In fact they are so immersed in their miniature race world, that should you get a chance to talk to one of them, you'll come out of the conversation, head spinning with terms like Camber, Toe in & Toe out, Gear ratio's, cutting comms

and other similar underworld speak. The point is, they don't just ride up and down the road in front of their house all day, they join a club and get involved with other like minded individuals. The same applies for All rc disciplines.
In short, no one rc discipline should be labeled "BORING". They are each and everyone punctuated with their own intricacies and peculiarities. It's about what "floats your boat" and how you go about finding out what really moves you.
Nowadays I fly Helicopters and Fixed Wing. I never enjoyed racing rc cars, because I don't really get excited about the big ones in real life. I'm a flying nutter, and I have a full sized plane to prove it. I believe that anybody, with most of their wits gathered about them, can fly a rc Aeroplane. When it comes to rc Helicopters, I still say the latter holds true. However if you have limited reserves of patience and discipline then stay away from them. But in most cases having like minded individuals with experience around you, goes a long way to easing the steep learning curve in whatever form of the sport / hobby you have chosen.
So, If you are not sure about witch way to go, my best advice is to attend some rc events that will give you a taste of all the rc disciplines out there. Once there, talk to the people, ask questions, because believe me, Rc enthusiasts are the best people to talk to about their hobby, and this way you will be better informed when it comes to making a decision, you'll also save yourself a lot of money if you make the right decisions up front.
The End.