What's the ideal height for bookshelf speakers?

I just bought a pair of Paradigm Studio 20's. They'll be delivered on Tuesday. I purchased a pair of Plateau speaker stands which are 30 inches. This will put the tweeters about an inch above my ears when sitting in my listening chair. The cone will be below my ear level. Is there anything wrong with having the tweeter slightly higher than my ear level?
That's fine. Assuming your head is not in a brace, its relationship to the tweeter will always vary a bit.
Try to find an adjustable stand. The height of the speakers can make a dramatic difference in sound (I had a pair of Sonus Farber E.A.II's, and they were REAL tweaky about height adjustment, although I can't comment about the vertical dispersion of the Paradigm.)
According to Sonus Faber, the optimal height for bookshelf speaker placement should be to have tweeter stays at the level of your at your siting position.

Need 2 persons to measure.
Usually the Tweeter is at Ear level!
In my room, my Sonus Faber Signums sounded poorly atop the 28" SF fixed height stands, but when I put them on 24" stands there was a great improvement in overall balance and significantly improved bass. This was surprising to me as when I owned EA I's and the variable stands they sounded great at the 28" level which I arrived at by trial and error, and never knew the height of, until a friend asked. I also had Concerto Homes and they sounded as good as they could sound on the 28" stands.

So what I'm saying is: try different heights and positions, and hear for yourself what works best. Then you will really know.
thanks everyone, I appreciate it.