You know, people like to crap on Flash (and there are valid reasons to do so), but I really miss how quick you could get a game built with it, while it still felt like "real" programming. With Flash, I felt like a nice "one-stop-shop" in a lot of ways; you could draw your graphics, animate them, and code them, and you could get a simple game made in an hour or two. I haven't tried Unity or really any other dedicated…
It will always be a cherished toolset to me.