So what do I, as a guy, think about women's nails? Honestly? I don't. Not usually anyway. On a list of the things a guy first notices about a girl when he sees her, nails don't even make the top 10. Even busted, nasty cuticles and chipped paint is not a deal breaker if the girl is pretty. But that said, nails are part of the package. Along with accessories, jewelry, eye shadow, and everything else girls labor about, nails are a small part of what completes the whole look that guys ultimately find attractive.
When I think about it, what nail color says to me most is "attitude." Bright red nails on a girl imparts a feeling of sexiness and maturity. Pink or a translucent color seems to belong on a shy, innocent, or introverted girl (sexy in a different kind of way). Black or eggplant can go with your goth outfit, but if you aren't dressed in goth, it still lends a certain extroverted attitude to your look. Any of the other rainbow colors like green or blue or lavender just means to me that you're playing around having fun with colors; They aren't really meant to be an everyday color but a cure for nail boredom. Then again, I'm a guy and this is just what I'm assuming.
On top of that color, a fun pattern is always interesting. Sometimes Peaches will come home with a stenciled pattern or something glittery on one of her nails. I think that's cool and I love a girl who is artsy and willing to switch things up.
But what about nail length? I personally like short nails without any fake tips on them. They're great for back scratches! Man o man, when they've freshly-cut, they have just the right amount of "bite" to put you in back-scratch heaven. But I also like the look of short nails. Not short as in "I bite my nails" short. But short as in a millimeter or two of white at the end. I never understood the appeal of nails longer than that--all the fake press-ons and such. They seem to scream "I don't want to do dishes or any type of work with my hands"
and "I spend lots of time pampering my nails just so my girlfriends can see how well I can maintain these useless fake nails." Long nails honestly have no appeal to me.
If fingernails aren't quite my thing per se, a girl having them done up in some sort of way can hardly ever be a negative. They're a fun thing for a girl to do, and one of the only ways to go crazy without breaking your workplace dress code. Plus, any sort of personal grooming that a girl does is attractive. But my favorite? Just a nice, plain, clean, unpainted or clear-coated nail. So honest, so pretty. I also like the kind of girl who likes to experiment with all the colors and fun patterns. But as a default, you can't go wrong with plain.