Martin Yan has had a couple, or more, series on PBS - and has appeared only as a guest on FoodNetwork shows. My PBS station is so flakey I never know if he is going to be on from one week to the next, even if it's in the TV guide. But then the GREAT cooking shows were on PBS - Julia Child, Galloping Gourmet, Frugal Gourmet, etc.
FoodNetwork did have some great shows a year or two ago ... but they seem to be moving away from cooking "instructional" programs (like Sarah Molton Live) and more to "junk" food programs (like $40 a Day, Top 5, etc.) Wolfgang Puck still has a program - Wolfgang Puck's Cooking Class - but it only comes on at 4:00am Eastern on Friday mornings!
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain