I've just got my 27" iMac and I'm having trouble with the wifi. Ive been tinkering for about an hour now but not getting anywhere. Over ethernet its blazing fast but soon as i take it out and use wifi its very slow. as an idea i was downloading the update for OSX and it was coming down about 8k/sec and predicting 12 hours. Router is downstairs, PC in same place picks it up no problem as does iPad, iPhone and all other devices in the house, OSX update didnt resolve it. Am I missing something really obvious?