We don't know. No info has been released yet. There is a new Intel platform (Centrino 2) being released in the second half of this year, so if you don't need it immediately you can wait and see what comes out of that. Other than that,...
The battery is sturdy, no more or less fragile than the rest of the laptop. I'd be more worried about the screen breaking if you dropped the thing rather than the battery.... much more expensive item to replace.
Not sure what you mean...
Does not really matter for the average user. Go with what you can get cheap if you want to save money. If you want quality go with Crucial, Kingston or Corsair, all good brands.
Stu
All you need is a SATA 2.5" hard drive. Brand, size, etc does not matter they should all work, inlcuding if you want one at 200GB (Note: IDE will not work, 3.5" desktop drives will not work).
Stu