iTerm2, the successor of iTerm, seems to be quite a bit better then the default Mac OS X terminal app:
If only every Mac OS X app (i.e. Quartz) would also support copy on select, middle button paste and the other X11-like features!  Further, I’d love to see a terminal app that disallows pasting (cmd-v) from the keyboard-controlled clipboard completely as this is potentially a very dangerous thing.
 Note: It’s possible to emulate X11’s behaviour to some degree using BetterTouchTool. It’s still not the same though as X11 distinguishes between the mouse-controlled buffer and the keyboard-controlled buffer and doesn’t just “paste from the clipboard”. For reference, see: