Googling suggests your screen name has something to do with Dante or T.S. Eliot ?

Yes, it's from "The Hollow Men"

Good point, but it seems that SIAI has one of the most pessimistic Singularity-concepts (especially if you compare it to the views of, say, Ben Goertzel, Ray Kurzweil or Max More) and therefore advocates strong precautionary measures, which in turn reduce x-risks.

But Goertzel and Kurzweil are speakers at the Singularity Summit! :-) I agree that the talks by SIAI staff at the Singularity Summit which address AI risk reduce x-risk, but it's not clear to me that the Singularity Summit is positive on balance.

True, in fact thinking about possible nuclear war made me realize how important x-risks are. My main arguments against working for organizations against nuclear war are: 1.They already have HUGE budgets ( e.g. from Warren Buffet) so my money doesn't make a big difference

Even if nuclear deproliferation is overfunded on aggregate there may be particular organizations which are especially effective and in need of room for more funding (the philanthropic world isn't very efficient). I agree that a priori it looks as though SIAI has a stronger case for room for more funding thanorganizations working against nuclear war but also think that the matter warrants further investigation.

The problem has existed for almost 70 years. Folks like Einstein and Russell, which I greatly admire, have thought about these problem for years and, well to be frank, I don't know if their efforts did actually decrease or increase the risks! Maybe strategies like MAD are better than the ones proposed by Einstein and Russell. So why should I have any confidence in my strategies?

I agree that uncertainty as to which strategies work drives the expected value down, but not to zero.

Whereas with regards to AI-x-risks SIAI and in particular Yudkowsky seem to be way more competent than the other folks. ( Excluding Bostrom, Hanson, Omohundro and probably others that I don't know, but the ones I find competent usually work for or with SIAI.)

I agree that the best people thinking about AI x-risk are at SIAI. This doesn't imply that their efforts are strong enough for them to make a meaningful dent in the problem (nature doesn't grade on a curve, etc.).

Are nuclear wars really existential risks? I think they are only Global Catastrophic Risks, i.e. they won't lead to human extinction.

I'm presently inclined to agree that the immediate effect of nuclear war is unlikely to be extinction (although I've heard smart people express views to the contrary). But plausibly nuclear war would leave humanity in a much worse position to address other x-risks (e.g. political & economic instability seem more likely to be conducive to unfriendly AI than political & economic stability). Furthermore, even if nuclear war doesn't cause human extinction it could still cause astronomical waste on account of crippling civilization to the point that it couldn't yield an intelligence explosion.

You can apply these arguments, mutatis mutandis, to global pandemics, biotechnology, Super-volcanos, asteroid strikes, Global warming and ,to a lesser degree, nanotechnology.

Some of your arguments apply to some of the risks but not all of the arguments apply to all of the risks. In particular, none of the arguments seem to apply to asteroid strike risk.

And, the final knock-down argument, IMHO: If you solve the FAI-problem you solve all the above listed problems, at a single blow!!!

This is definitely a point in favor of focus on FAI but it's not clear to me that it's a strong enough.

But, I could be wrong! No, hopefully I'm wrong! Because the likely conclusion of my reasoning is the following: Work in finance and earn money in order to donate to SIAI! That sucks soooo much, to put it charitably.

(a) The existence of any x-risk / catastrophic risk charity with room for more funding suggests that donating money is highly cost-effective.

(b) Donating money is not the only way to reduce x-risk. One can work against one of the risks oneself (e.g. work for SIAI as a volunteer, work for a government agency working on one of the relevant x-risks). One can also try to influence the donors of others.

(c) Regarding your discomfort with the lifestyle that your reasoning seems to lead you to, see paragraphs 2, 3, and 4 of Carl Shulman's comment here.