I still find Balsamiq super useful.

It's still my go-to tool for mockups. I find it to be the most powerful tool to convey product behavior to stakeholders

Yes, was about to say the same, then saw your comment.

IIRC, Peldi, Balsamiq founder, had blogged about it at the time. I like it too. Also reminds me vaguely of the Comic Sans font, which was the rage even earlier.

Perhaps more like Tekton, which was like a classier crisper comic sans

Wasn't there an X window manager that you could skin in the same way?

Compiz?

I use it almost every day.