I like it colder. The batch I made last year, when it is served cold it improves the crispness of it, it's almost like Champagne in a way. But I'd have to experiment now that I left some 'still' (flat) this year.
Sorry, had to vote Nader on this one... while most of my cider consumption (and my preferred) has been cold, I will also sometimes drink it at room temperature ('samples' from the fermenter) or warmed (mulled) around the holidays.