In reply to Cake:
I've been running for about the last 18 months. Running hasn't improved my climbing per se. I can't say I have noticed any difference with recovery times or anything.
It has made me fitter overall so I can handle long walk ins and long days better. As I do most of my climbing in Scotland, I can only think of this as a good thing, and it makes alpine trips much more pleasant as well.
I think it is worth doing some form of cardio exercise if you aren't already, not for the benefits specifically to climbing but because of the more general benefits that CV fitness brings (and because a good cardio session gives me a high like (almost!) nothing else!). However, as others have said, if you don't like running, don't do running. It's hard on your body and you won't stick to it if you don't enjoy it. There are plenty of other things you could do which would give you just as much benefit.