I took a stock plan and customized it. Obviously, take your HT into consideration when starting with that stock plan!!! Don't worry about the kitchen! lol ;-)
I actually redrew the plan onto my Macintosh at the time, and drew furniture at proper sizes, etc. It gives you a better feel for room size.
I would suggest getting a cheap Home Builder program for your PC. You'd be surprised how those programs can help you get an idea what YOU want before you go to your contractor, or before you start contracting things out yourself.
They also provide 3D views that help you and your spouse a lot. Some provide walk-throughs of the whole house that can provide a real feel for the house.
In fact, my answer (had it been shorter) would be to buy a decent House Builder program for your PC (you don't need the crazily expensive ones, nor the really cheap ones) that have many, many built-in house designs and that allow you to customize those designs. Get one with 3D capabilities if you can. Most do.
... Greg
P.S. I only wish they had those programs out when I built my house, but I'm glad I used the computer for the job. There's lots of little areas in my house that I love that I only "discovered" using the computer.