What a tricky subject...
We've all been taught that it's wrong to tell a lie but I agree with Thorne that it completely depends on the "type" of lie. For instance, he mentioned telling someone they look great when they obviously don't. It's just a little boost for your friend or loved one and where's the harm in that?
This goes hand-in-hand with Oz's comment as well about the motivation. Although what's that old saying about the road to hell being paved with good intentions? Slippery slope, there.