I'm anal to the point of driving myself insane sometimes. I have long tried to come up with a standardized way of labeling individual movements for classical. The system I currently use is:
<kind of composition or name> for <instruments> <number in series> in <key> <"nickname">, <opus> <number>, <catalog designation>: <movement number>. <movement designation>: <tempo>
Some of these are optional, since there isn't always information to fill in for each item. Here's an example track:
Piano Sonata No. 23 in F minor ''Appassionata'', Op. 57: I. Allegro assai
Notice how I flipped the work and instrument designations. Across my collection there are inconsistencies here, and it drives me nuts. Unfortunately, whereas "Piano Sonata" sounds better than "Sonata for Piano", if you've got something like "Concerto for 2 Violins, Cello, Strings, and Basso Continuo", that definitely sounds better with the composition kind first. So it's a judgment call, and as I organized my library I vacillated between these two orders on a somewhat arbitrary basis.
Apart from this stuff, I try to fill out all the categories as best I can given available information. When I find a mistake I'll correct it immediately, even if it means hunting down my portable player and synchronizing its library with the main one.
And don't get me started on capitalization rules. I've finally decided to just go with how the back of the album renders it, even if that means that sometimes I end up capitalizing words like "the" and "a" and other times I don't. And numbers? Should one use numerals or write out the words? Again, I just go with what the album officially uses. The prescriptivist rule, incidentally, is everything under ten should be written out, ten is discretionary, and everything above ten should use numerals.