I watched the dterm video, and it looks interesting, but the lack of an apparent scrollback (as soon as I type a different command, the previous output is gone) would bug me. (Plus, does it support history, including search, etc?)

I'm using TotalTerminal - it's not context aware, but it's easier for me to launch it with Ctrl-` than to open a new virgin terminal whenever I need to do something really quick.

The only real win for dterm is the context-aware factor, but I find it to be a big-enough win that I keep it around. If you just need a quick virgin window and are using iterm2 (as you should be) then you can go into Prefs > Keys and set the global hot key toggle and then select the 'hotkey toggles a dedicated window with profile' to get a dterm-like overlay window that is a real terminal session.

I can't imagine life without Guake. Nice to see that OSX has its own version. In fact, I now do all of my development in Guake with tmux and Vim.

GrandPerspective is pretty terrible.

I recommend DaisyDisk instead - http://daisydiskapp.com

DTerm is fantastic. It's not something I use often but the times when I do need/want it are what makes it fantastic. A simple example is that I wanted to make a txt file on my desktop so I hit the shortcut, typed touch x.txt and bam, there it was.