I like the Intuition GTK theme, but its window decoration lacked some things I like. I want active and inactive windows to look different, so I made inactive windows' titlebars transparent. I also replaced the buttons with the ones from the Wombat Glass theme, modified so that the border is invisible until pointed at, and there's a slight tan highlight in the borders of pointed-at buttons. This makes it look a bit like the GTK theme's buttons. I might try to replace the Wombat Glass theme's min/max/close icons with Intuition's original icons in a future version.
I'm a bit unsure of the license. The Wombat Glass theme, whose buttons I used, is GPL, but the Intuition theme is CC-by-nc-sa, which seems mostly GPL-compliant except for that non-commercial clause.