I use a Wacom Graphire 4x5 tablet daily on a dual-display setup and find it perfectly adequate for design work. I purchased it refurbished for around $50 and couldn't be more pleased with it. It has done wonders for emerging carpal tunnel syndrome symptoms I had in the past. I find the hand position for holding the sylus much more natural than any mouse, no matter how ergonomically designed.
I suggest going to an office supply or computer/electronics super store and trying out the various options yourself to see which one fits your personal tastes. Obviously, it will be different for each person.