I definitely believe in mixing meals up with good, nutritious supplements. I myself enjoy cooking and eating, but even I wouldn't have much of an appetite if I had to eat the same thing every day!
My guys aren't picky eaters, but they're always super interested in trying something new. And though I don't know for sure, I bet higher quality kibble just tastes better to them. Instead of getting artificial "flavor enhancers," they're tasting better quality ingredients.
Check out sites like Dog Food Chat (http://dogfoodchat.com/), Dog Food Advisor (http://www.dogfoodadvisor.com/) and Dog Food Analysis (http://www.dogfoodanalysis.com/) for extensive reviews on many different kinds of commercially available kibble. Hopefully there is more than Eukanaba available in your area!
Other supplements I like to add (and they like to eat!) include raw egg, beaten and poured over kibble, fish flakes (I get them from Asian markets, but you have to check the ingredients carefully as some of them are loaded with MSG – Japanese brands tend to be better about that than Chinese brands), baked mashed sweet potato, etc. I also like steaming vegetables and adding them to the food, but my Basenji picks out almost all vegetables. If you prepare fresh vegetables ahead of time, say once a week, it doesn't take very much time.