I'm pretty sure it shouldn't happen, but can't figure out what is wrong.
I use a cutting-edge Arch Linux install (KDE 4.6.5, everything up to date, latest VLC 1.1.11, works like a charm), and noticed that VLC didn't inhibit my screensaver. For instance, Dragon Player does.
It may be completely unrelated or not, but there's something else that doesn't work properly : when I start VLC, I have to wait for about 1 second (SSD drive) before it appears. Sometimes for several of them (non SSD drive). It used to be almost instant. (I don't refer to the first start of the app, but after quitting & relaunching it). Maybe something related to dbus or qt versions.... ?

Cheers ! & THANKS A LOT to the developers, been using VLC forever !