[CrashBangWallop]

Best thing to do would be to go to your 'local' club and see what everybody else is running to get some sort of idea of what you are going to have to spend.

Li-Po packs can be bought relatively 'cheaply' and it's more of a level playing field compared to Ni-Mh's used to be. Aim for high capacity and high 'C' rating e.g. 5600mah 60C.
Chargers have changed but most will still charge Ni-mh's / Ni-Cd's (why ?), as well as Li-ion, Li-Fe and Li-Po ( the one you really need ). You do need to 'balance' charge the 2 cells in the pack - this basically means both cells are charged individually to a maximum voltage of 4.2 Volts per cell in the pack. Invest in a good charger and a 12v power supply.

ESC - Go Brushless & sensored. Simple ! Everybody will now suggest that what they use is the best and you should buy that ! Speedo of the moment - Hobbywing V3 / programmable and lots of support from forums by way of settings.
Slightly older but still a goody in my book Tekin RS PRO or RS, programmable, lots of support from manufacturer - you can actually talk to the man ( randy pike ) via forums or email at Tekin in the USA and loads of settings available and 'regular' updates.

Hope this helps a little