I've not regretted buying a bike without ABS yet...YET...Hopefully I never will.
I do wish my V had ABS though. The only time I really wish I had ABS is when riding in the rain. I'm pretty good at braking without it under ideal circumstances but not having ABS when the roads are wet or having to do some emergency braking in a turn is unsettling to me. I practice emergency braking but I don't do it on wet roads or while in curves because the risk of pushing that envelope feels too high for me, I don't feel like highsiding for the sake of practice.
I attended a BRCII class just yesterday just to bone up on skills and get a fresh perspective. There aren't any Vs in this area and it kind of drew a crowd. No one believed me that it didn't have ABS. the V and myself were braking better than the bikes with ABS because I've gotten pretty good at modulating the brakes, bringing them right up lockup and then backing off a bit. It made for some very short and predictable stops that seemed to amaze the instructors. If the parking lot had been wet, I would've been screwed because, to be honest, locking up the front end on a wet road scares the **** out of me.
So, I don't regret it now but if I ever need it, I will.
My next bike will probably have ABS