They say you should never use the email address provided by your ISP as your primary email since ISP email addresses are not transferable between ISPs (as phone numbers are in most countries).  Unfortunately there are some times when you can't avoid using provider email such as on mobile phones, so if you ever decide to change providers you can take your number but you'll still need to inform everyone of your new mobile email address.

While passing by one of the shops in Akihabara I happened to catch a glimpse of an Eee PC but to my surprise it was not running Linux but Windows XP home edition.