I know the economy is not well. Money is tighter for everyone. One easy way to update your wardrobe, without spending a small fortune, is by reinventing what you already have. Just employ your local (expert) tailor. Designer Martin Margiela isn't known for his creation of new trends; he expertly tailors classic designs and presents them refined, refreshed. And you can do the same.
This fall, coats and jackets are perfectly polished. Have your tailor reshape or resize your blazers and suit jackets. Strong lines show class and confidence. Think visible darting. (A dart is type of stitching that creates a curve in the fabric and allows the fabric to drape well, conforming to the shape of the body. The darts in a garment are what make the garment fit.) Consider shortening your trench coat, so it falls right at the knee.
And don't forget your pants either. Have the legs on suit pants taken in. You don't want them to be so tight that the fabric bunches (like Dior Homme's skinny jeans), but you also don't want them baggy (like a suit off-the-rack at your local discount retailer). Even consider trouser cut denim. A well-dressed man is dressed well all the time, not just during the work week.
Some trends come and go, but others remain unchanged. Black tie will always require a black tie. That's been the staple dress for formal occasions since the 1500s as dictated by Spain's Phillip II. Think elegance. Think sophistication. Think understatement.