BILLDOUBLEWIDE  Nevermind. It was an incompatible login item (not sure which one yet) that caused the problem. Plot seems to be working fine with Snow Leopard. Hurrah.  
(Version 0.997)

BILLDOUBLEWIDE  Oh, no. Upgraded to Snow Leopard and Plot is not happy about it. Menu dialogs don't seem to respond. Existing files open okay via the Finder, though.

Hope there is a fix or workaround. Brilliant program. Top-notch.  
(Version 0.997)

BILLDOUBLEWIDE  I still use over terminal.app. Why? Two reasons: 1) iterm had tabs before terminal, so I got used to it and it's shortcuts, 2) ability to set "characters considered part of word" in mouse preferences. This allows double clicking on a path or url and getting the whole thing all at once. Sounds like a little thing, but it is one of those little things that makes life so much easier.

I don't understand the transparency issues, perhaps that was with an earlier version. I like being able to turn transparency on and off command-U (or setting a bookmark with always off). More convenient than terminal.app, IMO.  
(Version 0.9.6.20090209)