Before we answer that question, we're going to talk about chopping in general..
Truth is, not many knives are designed to handle the abuse of chopping (like an ax is). A dedicated chopper is heavy enough, big enough and has the proper balance (weight forward), but there's much more to it. The blade has the right geometry, with plenty of supporting mass behind the edge, and the steel is heat-treated for the rigors of chopping.
Sure, you can try to chop wood with almost any big fixed-blade. Before long you'll discover, though, for better or worse, what kind of knife you have -- if you need to take mighty swings to make chips fly, trust us, it's not a chopper.
The other sign that you're using the wrong tool for the job is, unfortunately, a damaged blade.
On the Web you can find countless pictures and videos of expensive knives with half-moon-shaped pieces missing from their edges. It's the kind of damage that results from either poor technique or chopping through an unsupported branch or twig.
Chopping something that isn't stable -- no matter how flimsy it may be -- puts uneven stress on the edge. Under those conditions, even a great knife can fail.
If you want to chop, use a tool designed for it. Little additional effort is required with a proper chopper -- design, weight and balance do most of the work.
Also, be sure that what you're chopping is supported and stable. If you don't, you're only asking for a chunked edge.
Finally, like most other aspects of bushcraft and wilderness living, the ability to chop isn't in a tool -- it's in you. It's a skill, so learn how and practice.
Ok, now we'll answer your question.
Bark River makes some great tools for various degrees and types of chopping. We're fond of the popular and time-tested Golok. Other excellent choices include the Bravo III, Canadian Camp Knife II and Pro Series Brush Knife.
Whatever tool you choose, always observe one of the cardinal rules of woodcraft: Don't chop when you should cut. Remember that cutting is all that most knives are meant to do, and working within a tool's limits is a priceless skill unto itself.