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As for a human, I always think of "shouting" when I see all caps, so I personally wouldn't use them.
That effect is generally negative in my opinion. Nobody wants to be shouted at, and the title shouting at you only makes you expect that the website will shout at you too.
Most search engines already boldface the keywords in your title tag that were part of the user search - that is sufficient for users to scan for what they want.
Anyway, having good snippet is now more important than just a position in SERPs, obviously you have to be in first 10, but good snippet can give you more than #2 or #3. And if you want to know what good snippet is, try googling for something yourself. I search for everything in G everyday and have no doubt it's not just a matter of eyecatching.
Eyecatching is needed if you put adds in material someone reads not bothering for adds. SERPs are different - searcher reads it, and looks for snippet assuring them they'll find what they want, so they need to show you're relevant.
Any editors out there? That would be willing to consider adding my site to dmoz for me? it could be financially benefitial for you.