How do you sort your LPs?

I really can't imagine any practice other than basic alphabetical filing. Yes, I have a separate section for classical, and also for greatest hits collections that include multiple artists. (I collect radio station greatest hits collections. Please don't ask why.)

My LP collection is large enough that it has to be spread over two floors. So for convenience, it is filed A through Z on each floor. And in my listening room, I have a small "hot box" in the rack to file new purchases as well as current favorites, so that they don't have to be constantly refiled.

Of course, whatever works for you is what's best!

By genre then last name alphanumeric. I'm just starting to try the discog thing. Thanks uber and big greg for the tips, nice.

I have 25,000 LPs, 7,000 78s and 7,000 CDs.  My CDs and LPs are organized by genre, alphabetically and by vocalists/instrumentalists.  There are many genres.  I have excluded Direct to Disc and Japanese 45 rpm/DD LPs onto a separate shelf.  I also have 5,000+ LPs not in the collection with 1/2 sorted by genre, alphabetically and others just by genre.  As to CDs, the large boxed sets are nearly all Classical and located in two rows on top of 6' long CD storage cabinets (I use Can-Am steel cabinets from Canada).  The LPs are stored in custom built wood/melamine in a music storage room (storage shed & garage for 5,000+ LPs).  The 78s are stored mostly in the music storage room by genre and size 10" and 12" on the bottom levels.  Also, unsorted in the storage shed and garages (I just haven't gotten to them and moved last year).  I don't have more than 100 CDs on a rear corner of my listening room-a major coup from my last home.  Just equipment and seating.   

I don't organize my jazz by artist as so many are multiple artists capable of filing.  The Poll Winners I did file under (Barney) Kessel but I had to put a Coleman Hawkins Encounters Ben Webster as a jazz instrumental group recording, Hawkins.  Sometimes, it is difficult to pick whose name will a recording will be filed under, especially jazz.  Not so much in vocal, classical or ethnic music.

Mostly listened to classical rock when I was young. Then came kids and of course life went in a different direction. Got back into music as they got a bit older and started listening again in the mid 90"s. So only three categories for me; Classic rock, mid 90's and later, jazz and other (movie sound tracks, comedy etc). Alphabetical within categories.