I'm going to be a contrarian and point out that coding on any laptop is just awful.
You want:
- the biggest screen, or pair/triple of screens you can get for your budget.
- decent keyboard. I need full-size - can't cope with those poky little laptop things.
- SSD beats processor and memory for builds in terms of productivity.
Coding on the move is uncomfortable, noisy, usually bad lighting and far too many distractions.
Read Joel On Software - specifically rule 8.
This, 100%.
Just get a desktop and plow as much money into screens and SSDs as possible, , install which e er Linux distro you want and off you go.