2.4 ghz, Brushless and lipo is the way to go. You won't believe the kind of run-times, consistency, and power the new tech has to offer. As far as which electronics to get that totally depends on how much you have to spend, I say check out what the fast guys are running in the class you will be competing in. I use a Bantam e-Station BC-6 charger and I'm very happy with it, but I have heard the cheaper (Turnigy) chargers are almost identical and appear to even use the same menu interface. Just make sure to get a charger that balances cells as well, which most do these days anyway.

The most important thing you need to know about lipo is that each cell needs to stay between 3.0-4.2v and never more or less or it can cause damage or even fire. That just means its important to have a lipo charger and an ESC with a low voltage cutoff, or run an external one on older ESCs without an LVC built in, and always be sure to charge with the proper settings and keep your cells balanced. Most of the new chargers now have fail-safes to prevent fires and battery damage anyway. The "C" rating is basically a rough estimate of the discharge rate that the battery gives in relation to its mAh rating, higher C is better but you really just need a battery that will supply a bit more current than your motor will draw. Unless you are running a hot motor (about 6000+ kv) or low mAh batteries, the really high C-rated batteries will be overkill and make no difference. Due to the efficiency of lipo power you will probably get 20% or more longer runtimes than an equivalent NiMh, and they have much more consistent power than the older types, so no more drops in speed as the battery loses charge.

There are tons of resources available for brushless info and sensored vs sensorless so I won't go into detail about that unless you have specific questions, in which case just ask. I hope this helps you.