I pretty much like all the discs in my bag too.
My favorite disc is whatever one of them is working the best that day. Could be my Flick. Or maybe a Buzzz. Sometimes the Viper is saving me stokes...
But after a little thought the ONE disc that is my favorite is my 150g Champion Leopard. Why? Six years ago when I started playing I wasn't getting much distance and I asked my nephew who had been playing for quite a few years for some advice. He said go lighter. So that day I ordered a Leopard. Why? Because it was the first lightweight drive I came across that was tie dyed. Being an old hippie, all my discs I bought in the beginning were tie dyed.
Short story long, that disc made an instant difference in my game. My first driver that actually went consistently 200 feet or more. And with accuracy. And it was so flexible I used it for just about every kind of upshot.
Don't get me wrong, it has it flaws. Into a stiff headwind it isn't pretty. And when you absolutely have no choice but to beat thru the brush, its lightweight gets knocked down easily.
In any case I lost that tie dye years ago, and the next tie dye, and the orange one, and the green one, and... Point is I still carry one. In fact I have four Leopards in my bag, (or more accurately, my cart) two 150g Champs, a 172g Champ, and a 167g Star. And the only reason I've lost so many is that I use it so much, its bound to come up missing from time to time.
Geez I'm babbling.
Everyone should own a Leopard