I consider a guy fashionable if he has his own put together look. He looks like he puts effort into his appearance. I like it simple and laid back. My friend is really good at this. He'll wear a white shirt some khaki's and brown shoes and look good w/o having to do anything out there.
I also like lookin' at emo/ scene guys I love their style lol.
typically, when a guy wears more fitted/tailored clothing... suit/tie/vest... a layered kind of look. I can appreciate a fashionable guy...but I much prefer it when guys don't look fashionable lol. I like it when guys dress simply.