I would leave my job in a second for 5k more a year. Admittedly I currently make less than 100k but that 5k more is 5k more money towards securing my family financially.
Yeah, folks tend to forget that not all engineers are in their early 20s, making $150k and content to live with roommates for the next decade (and possibly the rest of their lives).
Speaking of salaries being before tax, in Australia for example you'd only see 63 cents in the dollar out of that 5k (assuming a salary of $80k a year, probably not unreasonable for a lot of Australian developers). Might you also consider extra time off? I've done this before, and at one place ended up negotiating 1 day off every second week instead of a pay rise; I still, more or less, got just as much work done in 9 days as 10, and neither I nor the company had to fork over more money to the government. Not to mention, a long weekend every second weekend was great for relaxation and opened up possibilities for my wife and I to travel slightly further afield than we could for a standard length weekend.