I did some preliminary guitar shopping a few days ago, at the only store within reasonable distance of my home, and I can't stop thinking about one of the guitars that I met there.
It's an Art and Lutherie (made by the same company as Seagulls), inexpensive, and what attracts me to it is its gorgeous appearance. It's royal blue; normally I'm turned off by unusual colours in instruments but this was different. The varnish let the grain of the wood show through and and matte finish (I know that's probably not the correct term) keeps it from looking tacky.
It sounds the same as every other guitar, to my highly inexperienced ear. It feels weird in my hands, but every acoustic feels weird to me since I'm used to a classical.
Would I be an idiot to buy a guitar for its pretty face? Rationally, I feel like I should be trying to ignore the guitar's appearance and focus on feel and sound. But to be honest, I don't feel able to competently judge a guitar's feel and sound, so maybe as long as it has a reputable pedigree I might as well go by looks. And I'm sure there's something to be said for choosing the instrument that captures your heart, for whatever reason it does so.