How should I deal with denialism or radical claims?

Back in December I came across this post on The Economist (via Tony's shared items), and I especially liked this paragraph:
So, after hours of research, I can dismiss Mr Eschenbach. But what am I supposed to do the next time I wake up and someone whose name I don't know has produced another plausible-seeming account of bias in the climate-change science? Am I supposed to invest another couple of hours in it? Do I have to waste the time of the readers of this blog with yet another long post on the subject? Why? Why do these people keep bugging us like this? Does the spirit of scientific scepticism really require that I remain forever open-minded to denialist humbug until it's shown to be wrong? At what point am I allowed to simply say, look, I've seen these kind of claims before, they always turns out to be wrong, and it's not worth my time to look into it?
I know that I need to be open enough to question my preconceived notions and be willing to change my mind on things that have been fairly conclusively proven to me if new evidence compels the change, but the entirety of my free time could be wasted trying to verify or debunk all the claims that people put out there. Where do I draw the line?

How much trust do I need to put in the expertise of the experts when they are working with data that is outside of my current understanding? But if I trust the established experts, I'll be lagging along with everybody else and disregarding those rare game changing thinkers when they happen to come up with something that truly revolutionizes our understanding of the world contrary to the established knowledge.

Do the ideas of the technological singularity and radical life extension, possibly during my lifetime, actually have merit even though they're outside of the mainstream understanding of the world, or do I give those ideas more weight than other radical ideas simply because I find them fascinating and appealing? I also find the idea of free energy appealing, but I no longer pay much attention to claims about it, so it can't be just about those things that I like.

Maybe I'm doing an ok job of weeding out the lousy ideas from the decent ones. I hope so, but I've got to remember to keep myself open to the possibility that I could be sorely mistaken in broad swaths of my knowledge, while also trying to avoid wasting too much time investigating frivolous claims.