Nothing is wrong with the names God and Jesus, etc. It's all about context. Like Chup said, whenever God's name is used in a way that disrespects him, such as casually or angrily calling upon him or swearing by him, it's taking his name in vain. If his name is said in a way that honors him, such as when in complete awe of him or of something he's done, or in prayer or thanks, that's obviously not in vain.
Hopefully this clears things up for everyone. It's not about God's names themselves; it's HOW they're used, the intent behind it. When in doubt, it's probably best to not use it.
On another note, saying God's name in vain is pretty much swearing--sometimes much worse. Using God's name as a curse is absolutely worse than a curse alone. Since swearing is against the rules, don't do it. Aside from the fact that it's disrespectful in general.