HDMI input on iMac?

I wish to play my Xbox 360 and get video and audio through my iMac.

I have a latest generation iMac. Is it possible?

You might look at this:

http://www.elgato.com/elgato/na/mainmenu/products/capture-convert.en.html

Anyone else got anything cheaper....that seems to have a lot of stuff I don't need.

As I understand it, I am going to need an active converter, but would prefer to spend under £80GBP if possible.

Thanks.

There is this at about 95 quid Belkin AV360 Mini-DisplayPort converter for 27-inch iMac Review - AV cables - CNET Reviews