I don't see any ghosting on my glowlight. Like you, I don't like to use a cover when reading and only use a cover when I have to put nook in my purse. For traveling (plane) I use a cover that I used with my first edition nook. I love that cover, has places to hold boarding pass, license, money etc. and glowlight fits fine for that purpose. As for stains on the white I am sure that it is possible. I use a skin from Decalgirl which does protect the white portion of nook.
I don't use a cover for my Glowlight either--seems to defeat the purpose of such a light device. I have a DecalGirl skin on mine because I figured the white would get pretty grubby over time. I keep in in a Nook sock--I took one of my husband's big heavy wool socks, cut off the part below the heel and sewed it shut. It's enough protection for traveling in my bag to work. If it needs something stronger, I slip a piece of heavy cardboard into it.
As far as ghosting, it hasn't been a problem on this Nook--there was some every five pages or so on the NST. (Just as an aside, I was looking at a Kindle Paperwhite at a store and noticed that ghosting was quite prominent.)