My humble understanding is that for food prep you would preffer a full flat acute ground blade. The narrower you go, the thinner it must be. If you get a wider blade, you could go a tad thicker while keeping the same angle for the grind. Anything with a saber grind (Mora) is going to wedge in whatever your are cutting (think potatoes, vegetables, apples, etc).
Something else to consider is whether are you going to cut on a cuttin board of free hand. On a cutting board a 8" Victorinox Fibrox Cheff knife is hard to beat (for the money) in slicing and dicing chores, but it is too wide to peel potatoes with it and too big to cut stuff without a cutting board.
With cutting board in mind, cheff knife, the size is up to you. Without one, narrower and smaller is better, but must be thin, paring knife maybe?
I own a Bark River Canadian Camp and a Bark River Aurora, both have been used for kitchen duty. The Canadian Camp does it much better due to the acuter grind. however, it does not compare to the Victorinox Cheff knife I have at home.
If you want a do-all blade, including wood processing and stuff... well, then anything goes. You could do everything with a Battle Mistress if you want.
Mikel