Seriously:
I personally know one person, I have a friend of a friend (that makes 2), and I've heard news reports about how those Glade Plug-Ins are VERY unsafe. They cause fires.
They do give off a lovely aroma, but think about how that thin tiny piece of plastic gets so incredibly hot, directly connected to an electrical outlet: bad news.
They will be taken off the market eventually.
And think of it this way: if a fire does start, who would be to blame? The multi-million dollar Glade company, or the guy / gal trying to hide her bong smells?
Be safe. Burning candles should always be in proper holders, too.
Vaporizers are a great solution, open windows whenever possible, and you can buy these little sock thingys that are scented and fit snugly over the blades of a ceiling fan, they work very well. My personal favorite is nag champa incense sticks.
NO PLUG INS! Safety 1st.