Wear what you are comfortable with. Your level of comfort and the elimination of akwardness should be first priority. If you are changing the way you dress because you think it is what others are looking for, you are selling others short and misrepresenting. Anyone who says you can't wear black is full of shit. If you like black and look good in black by all means wear it. I don't like the way I look in blue and I would feel uncomfortable wearing it. Charcoal is fine but if you dont like it-don't wear it.
Buy a suit off the rack or even buy separates, (custom will always be best is can be very affordable in comparison to some high end department stores) but always have it tailored to fit after the purchase-and take it to a real tailor not the dude at the department store (if possible, and unless it is a nice place like Neiman Marcus or Nordstrom, Macy's is probably ok) and not the drycleaner at the end of the block.
If you are worried about what others will think, or if you are uncomfortable wearing a suit, dumb it down to the lowest common denominator and do what you think they want, but, have a legitimate reason for the way you dress and be confident in that reason.
Don't wear your suit for the first time when you interview. Always dryclean the pants and the jacket together. Don't wear your jacket while driving a car and if you have to take off the jacket, fold it over the top of a chair-back rather than hanging it on the back of a chair. When you are standing or walking, button the jacket. when you are seated, unbutton it. Don't wear striped ties with striped shirts. Remember to cut the pockets before you wear it-they are often sewn shut. Shine your shoes and for wear leather soles not rubber.
For more info I think there is a good article about men's suits and fashion on artofmanliness.com