I can't believe im saying this but JC Penny has some nice and affordable 'office' wear. The Evan Picone stuff is not frumpy, always on sale, and lasts a long time.

I am in my 30's and never in my wildest dreams would think of shopping for 'modern workwear' at an old lady department store lol. I was turned onto it by a woman at work who always had very smart looking/put together outfits and now rarely shop anywhere else for slacks/blazers/suiting.

If you are looking for luxury though, Banana Republic has lovely fabrics and will do mild tailoring for free.