I'll be honest here, most of the time it is the G.A.S factor.
Personally I don't like a brand new guitar (I tried and ended up selling it). Not sure why, I guess I'm too scared to scratch or dent it and that brings down my connection with the guitar.
I prefer to hunt for used guitars with couple of dings/scratches, I like the naturally reliced look. Put some effort to clean it and set it up myself, this is the most fun part and it's like an addiction for me and it also builds a personal connection with the guitar.
Price wise depends on the build quality. The main factor is the guitar is not overpriced by the brand or condition. Oh yeah, used guitars are usually cheaper too
I could play well on a cheap Yamaha PAC112J up to SG-1000/SA-2000. These guitars are great and not overpriced.
Although I do agree that guitars customised to suit ones needs are like the "thing" for serious musicians, I am still rather influenced by branding and the aesthetic appearance of the instrument. Residual values play a part too. I would like my guitar to retain it's monetary value, due to either it's rarity, or because it's a collectible classic/vintage piece.
Having said that, intangible factors such as the hard-to-define "feel" and overall playability of the guitar are nevertheless important factors contributing to my choice of guitar. I am very attracted by the aesthetic appeal of certain PRS "10 Tops", but the guitar doesn't really "speak" to me when I cradle it in my arms... This is one reason why I am averse to purchasing guitars over the internet