Hi Guys.I have a 1.8 ghz mini and it is great,reliable and quite.I'm interested in purchasing a 20 inch imac at the apple store.I would probably be going with a refurb.I am concerned with the imacs reliability.Is there a serious issue with shutdowns? I cannot afford to keep both.I want to sell the mini and put some more in for an imac.Is this wise or should i just hang on to the mini and not risk it? thanks.