young fella at 21? I'm even younger than you are, 19!
Fact is, just as many college girls like the sleek look as girls who like the dirty/thug look; I'd say more girls prefer the sleek look, IMO. Difference is, you can also wear these clothes at parties or work and actually get some respect, which you can't do while wearing a $150 jeans from Diesel and a $50 battered shirt from Abercrombie!
I'd say drop the suits and 2-3 grand will be enough for everything you can wish for: slacks, shirts, some ties (not necessary, maybe a couple), a couple of belts, couple of jackets (one black leather, one brown suede), couple of sweaters, 2-3 pairs of shoes, and whatever else I'm forgetting.
I did the same thing a few months back and I've almost lost interest in my old clothes

If I were you , I'd stay away from some of these crazy stores (e.g a D&G shirt will cost way too much when you consider it's not even universally appreciated). You wanna stick with stuff that fits well, looks good, and is appreciated by as many ppl as possible. If you love styling but still have a budget, that saying should make it easier to get the look you want.
P.S - You wanna complement the high end clothes with some accessories that higlight your youth, etc. This can be done with the shades you wear, or the watch, the haircut, or even one of those Abercrombie necklaces.