Nah, while LCDs can burn in from displaying the same thing over a given amount of time, when they're off, they'll recover from that burn-in (unlike a CRT where it's permanent).
That said, with LCDs the backlight is what can make for an unusable screen someday, whether or not it's at full brightness, or low brightness matters none, just how many hours it has run, and the colors on the screen don't matter any either since the LCD itself is just a light filter over the backlight.
Also, this applies to desktop/laptop LCDs, if you let the screen sleep so aggressively that it's turning off after say, a minute of use, you'll probably burn out the inverter quicker, lol.
It sounds as if you can never win, but generally they'll last for a really really long time - I have yet to have an LCD burn out on me and I've got some computers with em that are REALLY old (a what, 15 year old laptop now? At least - it has a B&W LCD!) - my desktop I used about 7-8 hours a day for 6 years still had a good LCD up until the day it was stolen.
Anyway, the only thing it sounds like that screensaver is good for, is distracting drivers, lol.
If they really wanted to distract drivers, they'd put a hybrid system in the car so that you could stare at how good your fuel economy is. I DON'T EVEN WANT TO KNOW how bad that must be for prius drivers, as I feel guilty if I check the EVIC too much.