As-salaamu `alaykum
I've heard this term a few times and each time different connotations are given. So I decided to look at concrete definitions...
Apple Mac OSX 10.6's dictionary gives,
a young, urban, heterosexual male with liberal political views, an interest in fashion, and a refined sense of taste.
A Muslim is far removed from the connotations of 'liberal' as we know it in a political sense.
Collins English dictionary,
a heterosexual man who spends a lot of time and money on his appearance and likes to shop
Oh dear lol. "Shaykh" Wikipedia says,
"...one definition of which is a man (especially one living in a post-industrial, capitalist culture) who has a strong concern for his appearance or a lifestyle that displays attributes stereotypically associated with homosexual men, although he is not homosexual."
I'm gonna be blunt here,
"Whoever imitates a people is one of them."
Taking care of one's appearance is one thing (a good thing!), but going beyonds bound is another. Every time I heard someone refer to someone as being metrosexual, they always merely pointed to one overly sissified guy who upon first glance you would think is gay. Always clean shaven and you would 'think' shops like a woman...
I think the obligation upon the Muslim male to observe a beard is enough to topple half of 'metrosexuality', and the need to wear loose fitted clothes and enjoin masculine qualities topples the other! And to top it off, the concept of zuhd (absenteeism) encouraged is Islam would be at odds with the love to shop etc.