Yep... safe as long as you get the download from official web sites.
PS... Oops... exactly what Floris said.
It took me years to switch over to VLC and now I can't stand to use anything else. My only gripe is it's difficult (not really supported) to have multiple VLC instances running at the same time. But I only rarely have the need to do that anyway.
Have never used GIMP but I know it's one of the oldest and most respected open source apps in the world.