"What's the coolest "perk" you've had at a job?"
Thank you for asking, Crust!
The coolest perk by far that I've ever had was going to Hawaii for work. My first job was working public relations in San Francisco in the dotcom era. Many of our clients were real, real dumb dot coms, but we also did pr for the tourism industry. One of our clients was the Hotel Hana Maui (which now has a new name, apparently, the Travaasa), but you can still see pictures here.
I got to stay for three or four days? I don't remember. I do remember that I had a jacuzzi on my deck and I took a two seater plane from Honolulu to Hana, Maui that was totally scary and ridiculously beautiful.
So, yeah. Free, all expense paid trip to paradise? Best perk.