I've been trying out Kupfer for a few days now. I heard about it from the guys at the Linuxbasix podcast. They gave an empassioned recommendation for this application launcher, but I couldn't make out what exactly what it was called or how it was spelled. If they gave the spelling, I didn't hear it and didn't go back to check because I was driving. Anyway I found the launcher.
It's spelled Kupfer! with an exclamation mark. And it is great. I was never really happy with Awesome's Command-R run prompt. Sure, it was predictive, but you had to start from the beginning. For example, you want gnome-screenshot, you can't just type screenshot and expect to get the app you're looking for.
But kupfer! does this. It's kind of like the Mint menu or Gnome's search in the way it predicts what you're looking for.
It's apparently desktop-agnostic, which is probably why it fits in so well with Awesome. It sits up in the system tray (I don't know why, but in Awesome, nothing looks out of place in the system tray). I've removed the shortcut key for the Awesome run prompt and instead mapped Command-R to open the Kupfer! prompt.
Apparently Kupfer! learns your preferences and all that. I'm loving it so far, but I'll give a more in-dept run-down of how I like it soon.
To get Kupfer to run at startup in Awesome I had to add the following line to my rc.lua
awful.util.spawn("kupfer")
You can get it over at the website. It's available as an Ubuntu PPA which is how I got it.