What is your bra preference on a woman? An unlined, push-up, or lacy number?  

I love everything natural about a women, including  their natural shape and the way their breasts fall.

I am with doncord.  Free the nipples, lose the bra.

Something about a sheer bra that drives me crazy

Natural?  Absolutely!  Breasts, AA through DD are all wonderful.  Push-up bras as well as implants are turn-off for me.

Had to google bra styles to figure out the names!  There's something so titillating about a sheer bra: it covers and yet you're able to see what's meant to be covered, and the result is a naughty turn-on.  Crafted in the style of a demi or, even better, the shelf or balconette and there's no longer enough blood to run my brain too.

Realistically though, whatever bra she feels most confident in will be the winner.

...as it doesn't look like body armor, or have sharp edges (those things that look like they were built for endurance rather than style)  I don't have a specific preference.  

Totally agree on sheer. I also love to see the sheer top and bottom combo.

If a lady is wearing a button up shirt or just a t-shirt for our date then bra-less is my preference.  Sheer is very nice as well as it does hide just enough to get the juices flowing.  Matching bra and panties no matter what the type are sexy as hell!

Matching sets are always sexy. Push up doesn't do much for me but sell lies haha

From a sexy lace is always great.  

I have even seen very nice athletic bras that can be a sexy look.

It won't be on long so braless is the best....but a sheer bra gives just enough of a preview and it's incredibly sexy.