Mens' Wearhouse is okay if you want a Sunday suit, but not so okay for a daily wearer. I bought four when I started in real estate (three different brands, too). All four completely unraveled in less than six months. And by 'unraveled' I mean just that. All the stitching came completely out of them. The jacket liners bit it first, then the outer seams.
Went to Dillards when they had a sale. Spent $50 more per suit and still have all of them to this day. I still get shirts at Mens' Wearhouse, but no longer buy my suits there.
Also, spend a few bucks on good dress shoes. Cheapo shoes will come apart, make your feet hurt, and usually end up stinking to high heaven. Count on spending at least $150 for a good pair of shoes. I know it sounds like a lot, but they will last many years with basic care and can usually be resoled for a modest price.
As with other posters, stick with the business basics for your suit - dark. Charcoal, gray, or navy pinstripe. Don't bother with vests. And shirts. White, or at least a solid color with a white collar and cuffs. Cufflinks are a nice touch, but only if you have some nice ones. Cufflinks from the dollar store just look cheesy. Ditty for a tie chain.
Jewelry. Minimal. Nice watch and, if applicable, wedding band and class ring. And as El Tejon suggested, clean. Most watches can be thoroughly cleaned with an old toothbrush and a dab of dish soap. Don't use cleaners or anything with grit. Jewelry can be cleaned the same way, although I recommend you take any rings and have them sonic-cleaned and polished. It's only a couple of bucks and really makes them shine.
And no nose rings, earrings, or other visible piercings. Period!
If you drink coffee, pop a couple of Altoids right before the interview. Chew 'em up good, then put another one in for a long soak. Coffee breath is as bad, or worse than, smoker's breath or funky guess-what-I-just-ate breath.
Stand up straight. Walk in with confidnece - like you own the place - but don't be cocky. Shake hands firmly, but not crushingly. Make solid eye contact. Speak forthrightly, but not to excess. Brevity and clarity are the key.
Brad