Recently I helped my good friend Igliashon Jones, aka City of the Asleep, prepare his newest album for its release. While double-checking the titles, I was reminded of how annoying and ambiguous the rules of title capitalization can be. For example, the word "throughout" is a preposition, but a longer one than most; to me it doesn't look right lower-case, nor does it capitalized. There are many other cases where what is correct is difficult to remember or conflicts with what looks good -- for a detail freak like me, this is a problem.
Some other languages with letter case, such as French, dodge the issue pretty well by sticking to sentence case for titles. For example, the title "Les barricades mystérieuses" is correct: only the first word is capitalized. Proper nouns (and basically any word you would capitalize in a sentence) of course keep their normal behavior.
In the past I used this sentence-style capitalization in a 1t1d project, where the titles were meant to appear more like accompanying phrases than official titles. The look appeals to me, and the rules are pleasantly clear. I'd like to explore this style for titles in my next release. If its charm endures, I may convert permanently.