I'm basically trying to decide if I should spend the extra $ to get the 24in iMac as opposed to the 20in, and my main reason would be to use it also as a second HD monitor/TV. So, I understand that the 24 inch iMac has HD type resolution. But, is it really HD, and if so how is the quality compared to an actual HD TV? And how would one watch HD content on an iMac except by downloading TV shows through the internet? There's no HD DVD player in the iMac, and you cannot get a TV signal in the iMac, can you? Thanks!