Welcome to the hobby/sport of RC. Listen, as a newbie, just read up on things, pick up a few magazines every now and then, and FREQUENTLY visit the RC-Tech forums like you are now. Head over to the track and check out some races if you're planning to race. Don't let all the rocket science talk confuse or intimdate ya... RTRs these days are WAY better than they were when I first got into RC. They're made by quality companies. Most of the RTR kits are upgradable, so you can add on the factory or racing upgrades as your skills improve. Associated gets an A+ on tech support.
* You'll get huge information and great responses here, but If you're planning to race, there is NO forum, magazine, or any type of advice that can measure up to actual "Practice, and on track experience"...Lap time is paramount.
* Invest your money wisely and check your local rc tracks to see what classes are racing there. A few of the popular classes right now are:
Vintage Trans Am racing (Vintage TA) (electric)...on road
8th scale Buggy (Nitro) ...Offroad
Traxxas Slash (electric)...Offroad
Look into these and other classes. Youtube is the best place to get good video footage of most any RC class going. Plenty of Vintage TA, Slash, and 8th scale Buggy footage on Youtube.
Welcome and good luck!