When I upgraded to 10.5 I lost one of my key "applications" - Visor. This is the type of application I need even more when I rely on virtual consoles such as Spaces in Leopard. But to my great delight I found a new update of Visor here :

Visor provides a systemwide terminal window accessible via a hotkey, much like the consoles found in games such as Quake.

[From blacktree-visor - Google Code]