I've been slowly compiling a list of things to bring based largely on this forum,
echolake: I am not a current mac user but I am waiting patiently for the new Macbook Pro update (supposedly any day now) to make the jump to Apple. From what I've read the software "Parallel" is best for running XP - I plan on getting that to run windows if needed. I PM'd slevit, one of the adamant mac users, and I think he would be best to ask if you had additional apple related questions - he was very helpful in answering my questions
dilzmega
I dont think the Macbook Air is what you want for your main computer on the island... I think it relies too heavily on wireless connectivity (not the best for an island with unreliable internet) and is targeted for the traveling businessman as a secondary laptop/light duty. If you are incredibly concerned about weight, than there are lighter and more practical PC's... I would go with one of the Macbooks or upcoming Macbook pro's and an external hard drive for your memory question.
Personally, I will be ordering a Macbook Pro 15" and a "Time Capsule"which is apple's new external hard drive and airport extreme in one. It's offered in 500gb and 1Tb sizes, both of which will provide ample room for data backup and for bringing all of my roomates' music to the island

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With the iphone - I dont think it would be best for the island. I have one now and have it unlocked; however, without a data network and limited wifi hotspots I dont think it would be as functional as it is here in the states. I think I will be looking for a more durable, practical GSM phone to take with me to school - perhaps a blackberry/palm out of the smartphone group
On a side note, I've been lurking around this forum for several months and its nice to see an increase in people posting for the May08 class... we should get one of those age/location/undergrad threads going, similar to what previous classes have done, to get a better feel for our classmates