Well, I play a lot differently than you do CG. I used to have a classical guitar, an old Yamaha whose model I can't remember. I've since given that to my sister. I love the sound of the nylon strings, but since my preferred playing style relates to a lot more strumming than yours, the wide neck of the classicals wasn't working too well for me. However, what I did like about classical guitars was the relatively flat neck profile (on the back where your thumb goes), and I think that's the thing I like best about my Guild D40. It has a flattish neck back that feels a lot like that old classical guitar I had, but the neck is narrow and more conducive to the quick strumming I do, but it's still wide enough to allow for fingerpicking. Now I've just said that what I liked about my Guild is a flattish neck, but oddly I played I think it was a Gretsch that had an almost pyramid shape to the neck. It wasn't a smooth radius, but had a distinct break in the curve at the high point. I really liked that too. My thumb has a tendency to wander, and having a point I can feel helps me to keep it positioned better. So I can't say that I want this feel or that feel too easily, but when I hold the guitar and play it, I have to like what I feel.
In general, I like a solid top. I have a cedar top guitar which is the guitar I think I play most. It has mahogany back and sides. It's got an unusual body shape that Takamine had a name for and which I forget, but it's very, very, very comfortable to hold. That's the next most important thing to me - comfort in holding.
It's got to sound good. So many pretty guitars, or guitars that feel good don't sound like much to me. I like a steel stringed acoustic guitar to ring out and have a good bass resonance. On too many, the bass is muddy.
Lastly, I want a guitar that looks good. This is entirely subjective and changes guitar to guitar. Joey and Detman have acoustic guitars with stickers on them, and they just suit their personalities so well that they look good for them, but I don't intend to put any stickers on my guitars. My cases are a mess, but not on the guitar itself. I don't mind scratches and dings and wear. I don't put them there intentionally, but signs of use improve a guitar's appearance in my opinion - but oddly like the stickers I don't want to see that when I"m buying a guitar.
So I guess it comes down to these criteria for me: feel, sound, look.
