Restaurant Tipping on Wine

[MontereyRick]

Read a rather heated discussion recently regarding this subject.

No doubt, the following question falls under the old "different strokes for different folks" adage, but...

Let's say it's customary to tip 15%-20% at a restaurant.

Do you tip on the wine at all?
If so, do you tip the same % as on the food?
Even if the server puts forth the same effort popping a $19 bottle or a $190 bottle?

I usually tip (if satisfied) at least 15% on the total bill, however, I've seen some pretty reasonable arguments recently for not tipping anywhere near that much on wine. Curious as to others thoughts.