Organizing the record collection.

I got a couple of new cases yesterday. I've had a lot of records everywhere in the house at the moment because they don't fit in the cases I've got because they are full already. I've had to improvise with some beer cases and other things. Now I can put in all the records that haven't fit into the old cases into the system... the problem is how to organize? 

I'm having everything in alphabetical order at the moment but I have been thinking about organizing either by genre or by year... dilemmas of a record collector...