Ergonomic Laptop for coding

Hello,

I'm new to the laptop world, so looking for one is pretty hard for me. But honestly, i'm mostly looking for which brand I should look in and why.

I heard HP and DELL are breaking easily.
ACER aren't good either.
Heard Lenovo were great, but the plastic break easily?

The ones I found OK were Toshiba, ASUS and Sony (not all of them), but I've look reviews and they all have 3.5-4 stars...

Usage:
Mostly coding, probably mostly c++. So I need a laptop which have a good keyboard layout ({,},Arrows,Home,End,delete,backspace,...).
I'll be coding mostly multi-threading/mathematics applications, so the CPU is important.

Maybe some gaming, but I wouldn't mind the settings at low/medium.

Requirement:
Ergonomy: For coding!
Screen: No more than 15.4".
Battery: At least 3 hours of battery, ideally 4.
Good Durability.
Processor: I guess no more than a i5, since the i7 most use too much battery.
Light (ideally bellow 5 pounds, or 6 if I must)
RAM: 4GB
Stockage: Don't really care... 320GB would do.


I was looking at the "Toshiba Satellite A660", but they only come in 16" and can't be customized.
http://www.toshiba.ca/web/product.grp?lg=en&section=1&g...

I'm looking anywhere bellow 1200US ideally (I can go a bit higher, but no more then 1400).

Thanks a lot!