Consider sound/tone...both in the guitars you have and the guitars you are looking at. If you want a stable of instruments to play a wide mix of music I suggest you look for a guitar that differs in sound and tone from those you already have.

I have three guitars; an acoustic dreadnaught, an electric semi-hollow body and an 12-string AE. Besides having the normal lust for fine looking/sounding guitars I bought the second and third ones specifically because of their difference in sound and their traditional use in different genres.

Many (most?) guitarists say they can hear the difference between brands, let alone types of guitars. Identify the sound you want to add to your collection and then look at guitars that deliver that.