Bad Dragon Rex for me, sure it's so well known and common that even some non-zoo non-furries know about it, but I think it has a pretty much perfect balance of realism and practical simplicity. The smooth shape is very easy to use, and BD's high standard silicone cleans easy, feels nice to the touch and holds lube on its surface very well. For how wide the knot gets it's fairly doable plus it's a classic. A Rex is less of a talking point for both the worse and distinctly, for the better, than say an Elypse Art.
If we were talking penetrables not dildos, then my American Meat two hole canine, I find it a bit too firm to use often but it looks nice and seeing it makes me a little glad to be born in our time when we can get such cool things.