Hi. I have all three, so my two cents: Get the Clara. It's more "different" from the Trophy. In fact, it's different from anything else out there.
India's right, the Corc is big for an everyday bag, though I have been using it that way. You will be able to fit more into a Corc than you would a Trophy if you're willing to carry it with the turnlocks undone. With the turnlocks fastened, it's similar size and shape to the Trophy.
One thing I love about the Corc, of course, is all those pockets -- all of which I can get into when the bag is on my shoulder. Small stuff that I need quick access to goes in the pockets. The main compartment will hold a book, water bottle, folding umbrella, makeup bag, pair of flats ... and you'd still have room for more. If you find your self getting really excited at that prospect, get the Corc, though as nice and versatile as the BP is, the Pewter or Khaki Patent, for example, would look more different than your ICP Trophy.
The Clara (I have the BZ) is just a really fun shoulder bag and it can do casual or dressy nicely. It will hold a lot (watch Toni's video!) but not nearly as much. The pocket in front is genius -- I can get into it without undoing the bag, so I keep my cellphone there.
If you like big bags. you will want a Corcovado someday. It is a very well-designed bag, with a lot of thought given to how you'd actually
use something that size. I can't say enough about mine. I have Pewter and I love it to death. But I think the Clara would satisfy you more at this point if you have a goal of developing a diverse HH wardrobe. I wouldn't pass up a great deal on either bag, though.
Hope that helps.