Each to their own again... I prefer proper case as personally I find it more readable. Keywords are highlighted differently anyway (working on the assumption that their aren't many cases where a developer would be working without syntax highlighting).
Interestingly UK (and many other countries) road signs are always in proper case e.g. London instead of LONDON as proper case is quicker to read
Code readability, much like object naming conventions usually comes down to systems. As long as there is a system in place, e.g. always trailing commas, always upper case for keywords and always using the same aliases for the same main group of tables (every system has a core of at most 10 tables which are used in 90% of the queries) then it doesn't matter what the system is as long as it makes sense and is stuck to within a team
I agree also (although being from England that may be why).
For anyone who has read a book on GUI's, most would advise to stay away from CAPITALS as they block out the screen more and make it more difficult to read. I always prefer lowercase, using capitals where words are joined and aliases even where there are no joins i.e. from myTable mt join anotherTable at on...
You never know when you are going to have to add a join in, and then you will need to go through and add them for the possible duplicate columns.