I bought a refurb 27" 2009 iMac and aside from the box everything about it looked brand spanking new.
The thing to look out for is whether it is a better deal to buy a current model refurb or find a deal at a place like Amazon or B&H Photo that does not charge tax. I bought my 2010 MBP last November, which listed for $1,799 + tax, from Amazon for $1,675 and no tax. At the time a refurb + tax was about $100 less than a new one so I went that way. Today, the same model, which is now last years, is only $1,269 at the refub store and a fantastic deal - I wish I waited 3 more months but that the game