What database do you use most often? Is it because you want to or some other reason? Is there a particular reason it stands out for you if it's because you want to?

I think most of use the database that our employer already has in place, and few have the luxury of "choosing" one. (Of course, you can choose where to work based in part on what database they have). I tend to "choose" mySQL for my personal needs because of it's price, but would probably use Oracle if money was not an issue.

To answer the main question, I currently use Oracle and Sybase mostly, and greatly prefer Oracle for the most part. I disagree with one of the statements above however - I vastly prefer case-insensitive databases, particularly ones that I have not designed, because it's real easy to make a typo when saying something like:

select Foo_Bar from ReceivableTransaction_Logs_Nightly
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(No, I wouldn't have come up with such horrendous naming conventions, but it's not often you work in a legacy-free workplace :)

Besides, SQL isn't case sensitive, so why not make the database objects the same way. :)