True pronouncables are long gone and quite expensive. The crowd is chasing what i call semi-pronouncables - anything with a vowel somewhere, in my cynical opinion. But sales numbers do favor pronouncables, real ones anyway.
The other major factors are acronyms and letter quality. Acronyms are valuable to the users of the acronym, but beware of trademarks. Also beware of well used acronyms with no sales value. So often I find a "popular" acronym that turns out to mean a complex protean in organic chemistry, or something like that. Yes there are a lot of searches on the term, but nobody is going to buy the domain name.
Letter quality means how often the letters occur in the names people buy. The most popular are S, A,and C. The least popular are Q, X, and Z. A LLLL.com with only S, A and C would be quite valuable, because many many acronyms would use those letters. It is unlikely that you will find a LLLL.com available to register that does not have at least one J,Q,U,V,X,Y, or Z. Domains with K and W recently became unavailable.
At the present rate LLLL.coms will become unavailable to register in about a year, so you should keep renewal costs in mind. And remember that domaining is addictive and there is no known cure.
