[Cothron Theiss]

+1 for Lenovo. I can't remember the exact model, but I believe we bought a Yoga 700 a couple years ago and have been very pleased with it, and it works like brand new. I think those run about $700 when new, but a used version may be cheaper.

I will say, with the $500 budget you can certainly get a great laptop, but do consider how many years you want to use this for. If you can squeeze two extra years of life out of a new vs. a refurbished laptop, it might well be worth going a bit above your budget.

EDIT- We also use our laptop for programming, and it is the holy grail of version control. Since multiple people are supposed to be able to use it at any time, we keep a pretty tight control on our version control and naming and commenting when code is on our main laptop.