I have two 8" chef's knives here at home. For most of my projects, those work fine. At work, I have a 10" chef's knife. I can cut steaks off of just about any cut with that knife. However, when I'm cutting ribeyes off a prime rib clod, I prefer to use my hollow-ground carving knife. The blade on that thing is 15" long, plus another 4" for the handle. I prefer that knife as I can trim the fatcap from end to end, working my way towards the "lip". Also, that knife is easy to slice through meat with, as that's what it's designed to do. The hollow-ground feature really does reduce the drag.
Pacanis, have you read through the knives sub-forum? There's a LOT of good info there. But, in all honesty, finding the right knife means you need to get your hand on one, and at least make some cutting motions so that you'll know how that knife fits your hand.