Depends on if you want an element of knock protection or abrasion protection. For me, skins usually do the job just fine if the machine is being carried in a laptop bag - and I only use skins for non-cosmetic purposes on Apples. If it's a bag without specific protection for a machine, then you'll need a sleeve. There are sleeves which include guides for a large variety of machines, not just Apple:
http://www.sfbags.com/products/sleev...eevecases.htm# I think it's very funny that many of the sleeves are for Macbooks and that far higher percentage of Apple owners elect to use some sort of protective covering. I've always throught it was an interesting understanding that Apple has of consumers, and the use of their predictable behaviour to Apple's advantage - i.e. making their machines fragile / 'precious' without impacting their rep for quality, and therefore 'guiding' the consumer into using it more carefully, which subjects the machine to less everyday abuse than a regular slab for people who're the 'the computer just died' types. It's one of the many little ways which Apple lets you know that
they know you're dumb - without the consumer realising it. Genius.
