What ebay-like sites are there in the UK?

What other sites are there in the UK that do ebay’s supposed job of enabling members of the public to buy used stuff from each other nationally? I’d like to explore other options but other than Amazon Marketplace I don’t know any.

Craigslist: http://london.craigslist.co.uk/

Gumtree too - http://www.gumtree.com/

List of UK auction sites - no idea how good that one is.