I currently have a 2.4ghz imac and a hp mini netbook. I'm looking at the Macbook Air units as a eventual replacement for my netbook but I can't decide between the apple 1.8ghz refurb SSD model or the 2.13ghz new SSD model. I'm going to use the macbook air for email, web, some light document work, and remote client into my work computer. I watch a lot of videos on hulu and youtube and I'd like to avoid video stuttering. There is a $200 difference between the two units w/ educational discount. So which unit should I buy? t.