Simple but useful applescript to be run by qucksilver trigger

I drink a lot (too much probably) coffee while working. I also like to lock down my computer while away fetching a refill, and I also listen to music while working. So, to simplify things a bit, I just created this simple applescript:

if appIsRunning("iTunes") then
tell application "iTunes" to pause
end if
tell application "ScreenSaverEngine" to run


on appIsRunning(appName)
tell application "System Events" to (name of processes) contains appName
end appIsRunning

and then assigned running it to a key-combo in Quicksilver.