Hi Neil...
I started racing about Jan 1993, so a good comparisons can be made compared to nowadays. Most things have got a lot easier to manage and look after nowadays in terms of maintenance.
1) Batteries: We are now able to use Li-Po packs, which do not require pre-charge balancing or any sort of discharging before peaking, then use. Just top up and go. You will require a Li-Po compatible charger, but these are very competitively priced. It is recommended to get a balancer/balance charger, since they often come with a cut off for the lipo packs to protect them during the charging process. Check your local clubs rules regarding charging, as they might say you need a 'safe charge pouch', which can be got hold of for a tenner.
There are several brands out there, including Reedy, LRP, Trakpower, etc etc. Check out the
BRCA website (under Electric Board) for BRCA legal (and recommended packs).
2) Motors/speedo's: Sensored Brushless systems, mean that there is no skimming of commutators on motors, and regular changing of brushes which is a godsend! Special attention needs paying to the gearing of these motors though, and checking of temps regularly. Also worthwhile checking your speedo temps (if possible). The Nosram and LRP speedo's even come with a way to check how close to thermalling you are after the race. Other makes to look out for are: Novak GTB, Speed Passion, Losi and Tekin speedos.
3) Transmitters: We are now on 2.4Ghz systems (no crystals) which means that interferance is now a thing of the past (99% of the time) if installed correctly. Well known makes are Spektrum (although you might be able to get hold of a Spektrum module for your transmitter (if its not too old)). You can get hold of these for KO and other transmitters.
4) AMB RC Personal Transponders: These are very useful (although very expensive). It means that you don't have to keep changing transponders after your race (which is much easier if you race on your own/don't have a pit man). Your local club will need the AMB Rc system to use PT's though. Best to check before buying one IMO.