@kimurastanley,
There are pros and cons; and v much depending on what you want to use the machine for.  If you're a hard core gamer, I would advice against getting a Mac.

no need to know the difference....now all models are unibody hehe juz remember unibody = good build quality
i used the Speck thing but a lot of ppl say dust can go in n somehow leave small scratches. i got the speck casing anyway and i opened it up n clean inside atleast once a week. i still get small scratches . n some of the clamps broke off cuz i take it out too often.

i got myself zagg invisible skin... rm110 in garage sales. very hard to apply, but at least i know my mac is protected

If you're talking about MBP aluminum unibody, then you can get either the Incipio Feather for Macbook (or Speck SeeThrough Satin) or a nice sleeve.
Thermal performance should around the same as the Aluminum unibodies. You just lose the surface heat dissipation capability.

it wont fit. the shape is very different

I love speck but they havent release casings for the new MBPs yet, which is

sort of troublesome I am relying and hoping my Macbook wont scratch.

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Added on October 30, 2009, 6:58 pmI mean, iinm, dvlz, it would fit, but it the casing would cover up the earphone input.