Speaking from a professional (chef/restaurant owner) standpoint, and a guy who does a lot of BBQ, my suggestion is:
http://www.macknife.com/professional.html
Not cheap but it will last forever and get the job done for you...guaranteed.
I've been using MAC knives in my kitchen for 10 years now and they're right on par with the quality you'd expect from any Cookshack smoker.
PM me should you decide to buy it. I'll suggest a sharpening stone that will keep this knife razor sharp. Running the edge through a standard knife sharpener will compromise the edge. The stone is under $20 and will put a razor sharp edge on any other knives you already own.