purchasing a new computer

I am going to get my first Laptop (notebook) computer, and was wondering
what things should I look out for, especially which models are the best
(below $1,500). I have my eye set on a Toshiba Satellite SA60-332, but
am also considering the Satellite SA50-432 (I want toshiba cause of the
3 years int. warranty)

However I have some questions;

Which is better; Pentium 4, 2.8ghz processor or Centrino 1.5ghz?
What is the bus speed and which is best?
What is the difference between Level 2 cache and the standard one, I
know it's the temporary ram on the chip, but what else. And will a Level
2, 2mb cache really be that fast?

Also, I don't mind changing brands as long as I get a really tough
notebook, I don't care about the weight or the size, be it 15kgs, but I
want toughness more than anything, can anyone recomend a specifc model
(other than the panasonic toughbook)

I hope that someone can help me out, thanks