A good woman will still smell good the next morning, even if you've been out all night in a smoky bar.
I'm with the Japanese coworkers. Women/Girl's sweat is the most intoxicating smell I've ever encountered. Especially a while after she's showered and then sweat a bit is quite nice. One of the girls I've dated in college would come into my creative writing class right after she'd been to tennis practice. It's no wonder I clamored after her. She'd just gotten a workout and her phermones were running wild.
If I have to narrow the scent origin down a bit, I'd say any time a girl's metabolism raises itself and hormones are produced is when my brain starts to make me think about making the guy-girl legos click. I'd say that most the time I notice the feeling is an exciting emotion and not just lust. I start to wonder if the girl is bright and intelligent and what she may like to do for fun. A friend of mine and I have had this conversation many times, and we have come to the conclusion that we just enjoy being around women most of the time.
To add to my list
I also like the smells of:
new electronics and their packaging, like the styrofoam in my 1987 NES and my Gameboy in 1989
new Tires
new leather
something baking in the oven
toast
really danky dank wafting in a breeze, down to me, on a cold day
chicken soup
the stale smell of books that seems to stay in my nostrils for hours
lavender
green clay
the morning smell of my grandmother's fried eggs when I was a child.
ozone-clean air before rain precipitates.
Dial soap before, after, and during a hot shower.
wet garden dirt in the summer time.