Hi,
Depends on a number of things. Mostly budget!
Everybody will suggest different things as usual with these threads, but I can help with some general info.
For 2WD it is normally motors in the 7.5t to 10.5t range. An 8.5t would be a good place to start. Good, usable power, but reasonably easy to drive. Then you need a speedo to handle it. Plenty around. You can quite often get 'combo' deals with motor/esc packages.
This kind of thing:
http://www.ebay.co.uk/itm/SKYRC-Brus...Fmb8DoadSssuSw
Not top notch kit, but decent.
If you're needing to stick to BRCA rules you may need to buy an ESC (No BRCA rules governing ESC's), but with a BRCA legal motor. Plenty around at reasonable prices...
Like this:http://www.ebay.co.uk/itm/Skyrc-Ares...IAAOxywFhTcyoj
I could go on and on. There are secondhand options too which can be a good way of getting good kit at lower prices.
Ask away lads!
Jimmy