It's too much of a classic to ever truly be dated. That said it's not one of my favorite names. If I had to use it, I'd use the spelling
Katharine and the nickname
Kat or
Kate. I don't like
Katie.
http://www.behindthename.com/pnl/72895
"Your assumptions are your windows on the world. Scrub them off every once in a while, or the light won't come in.” ~
Isaac Asimov