Wait, So we have to sound good on a guitar in order to justify owning it?!? Oh crap. Looks like I need to sell, well, all of my guitars if that's the case.
Back to the subject of the thread. The most expensive guitar I own has to be my 1970 Les Paul Custom. (At least, I think it's ~1970. Gotta love the preciseness of the Gibby SNs during that era). It's a Black Beauty "fretless wonder" that I bought for $550 used many, many years ago. After I injured my wrist and could no longer play, I sold everything (including, yes, a 4-digit Standard) except for the LPC. I just couldn't bear to be without a guitar, even if I couldn't play, and since the LPC was steadily appreciating the most in value AT THAT TIME, I figured it made the most sense to hang on to the LPC. Well, that and the fact that it sounds absolutely killer.
Fast forward many, many years and I'm able to (sort of) play again. My wrist still gets inflamed but not quite as badly as it used to and at least it's allowing me to play a little so that's better than nothing. I still suck but that's to be expected. Hell, I sucked even before my wrist injury so no change there.
Still miss that pencil-neck 4-digit though.