You can tile right up to the underneath of the hood. This will look very professional.

But don't let the tile touch the hood. Leave a 1/16" between the tile and hood, and caulk this line. Get a tube of caulk from the tile supplier that matches your grout.

::pointing up:: WHat green said :oP (exactly what I'll have)

Thanks! The caulk can just be the same stuff that I use between the countertop and the tile, right?

Oh boy, here goes nothin'........this is going to be the trickiest part of the backsplash, in terms of layout, and I'm stalling. :)