If you dont want HD then I would say DM500 Clone (£50) OR DM600 clone (£95).
If you want HD with single tuner then I would say DM800HD clone (£200 from uk but around £145 from china, as long as you dont get hit by customs). If you are going for a DM800 HD clone then make sure you get one with sim 2.01, bootloader 76 and Tuner rev L - this will mean you can use your favourite images unpatched.
If you want a dual tuner HD box then would suggest the VU+ Duo (£380) - this is a brilliant box and at the moment i cant fault it!!!