The existence of these three unregulated nuclear arsenals outside the NPT has been a problem for many years. Now we have a fourth, North Korea. To do something about this should be the very highest item on the agenda. The agreement that the United States has negotiated with India, at least in part, is motivated by that effort.
I personally have significant problems with the agreement in its current form, but I do support the objective of the agreement, to try to bring India into the international non-proliferation system.
Pakistan and Israel are very tough cases, but I have written an article about how this could be accomplished. It appeared in the Bulletin of the Atomic Scientists in 2004. We don't have time to go into it now, but I believe there are diplomatic solutions that could bring these countries at least into a relationship with the non-proliferation regime. They're not going to give up their arsenals overnight. We could bring them into a relationship with the regime and have them regulated in some way, have some limits on them.
If you're really interested, I'll send you a copy of the article.