I don’t know if I like it for nostalgia and geekiness, or just plain geekiness. There’s only one thing I’d change with the terminal theme… make it truly like the BBS experiences of 15+ years ago. I want ANSI animation and color ANSI art–especially for the Gmail logo.
Added: Even more importantly, the terminal theme works great if you get LISTSERV mailings that have tables rendered in all ASCII characters or code.