You can't go wrong with the Freecom usb DVB-T stick. Many favourable reviews. Around £22
I will say I bought
this couple weeks ago. Mainly because I don't like the software that came with the Freecom by default, so perhaps its for you. The stick isn't as stylish but the aerial adaptor thing is better designed than the one that comes with the Freecom
btw forget the portable aerials included. You will need to use your main roof aerial