Kali

Has anyone got any recommendations for a decent setup to run Kali for pen testing

Depends I guess. I run Kali in a VM with OSX as my base OS.

If I were running it as a base OS I would probably be looking at a workstation class laptop with a decent GPU for hash cracking. Something from Lenovo (t540) or Dell (M4800).

The recommendation for me was to run Kali in a VMWare VM using an appropriate USB wireless card passed through direct to the VM.