This is quite a topic because it goes into how a suit fits you and what is appropriate.
What fits you and wears the best may not be good for business. And what you can wear to the office may make you look like an amateur.
Here are a few pointers. Again this is just my opinion.
1. COLOR: Dark Navy or Black suits look professional and lend you a level of credibility. Pinstripes are in season lately and gray sublte pinstripes may give an air of confidence to an otherwise boring suit. Gray is a cool alternative to black, but I'd stay away from brown.
2. FIT: Dont buy a coat that's too big, or you will look like an amateur.
3. STYLE: Double breasted is nice but a bit too flashy. Keep it conservative.
4. SHIRT: Solid color relatively thick white dress shirts are a good bet. Don't buy a see-thru shirt, it will sink the rest of the suit at first glance. Blue or gray hues are acceptable. Yellow can be standoff-ish IMO because yellow and black combo is threatening in nature. Other light pastels may work, but tone it down with a conservative tie.
5. TIE: Easy to make a mistake here. No hard and fast rule, as I see it, but should complement the suit. I prefer solid colors or solid colors with a light boring pattern overlaid. Should have darker hues with a black suit, gray with gray, and should'nt clash with your shirt. I'm not qualified to speak on ties really, but as long as you dont look like a stop sign, youre ok. here's help
http://www.mens-fashion-tips.com/mens-ties.html If in a panic, just pick an older looking dark colored tie and throw it in a half windsor knot. Shows you can improvise.
6. BELT: Any color as long as its black. =) Shiny, solid black with silver buckle. Brown may be substituted if you have a dark gray or brown suit.
7. SHOES: Think of these as rims, and you suit is the car. Wingtips or oxfords in black are the safest bet and also most professional looking. They must be black (or brown to match the belt) and SHINY. Loafers make you look cheap. Square toed shoes can be worn if the rest of the suit is stylish and modern, but they should never detract from the suit, merely highlight your sense of style. I've seen many suits made null and void by ragged dull scrappy shoes. A wide brimmed sole makes them industrial looking and can also sink your suit.
The most important thing however is to wear something that fits you well and makes you feel comfortable. If the suit is wearing you, it will be a distraction for both you and the interviewer.
It should presents you as professional, knowledgeable, and personable so you can get the difficult questions out of the way and start talking about important things .... like golf.
8. WATCH. Bonus section. You could get the Omega Seamaster and go 007 on your interview, but generally a watch with leather band is most appropriate and tasteful choice. Seiko, Fossil, Citizen make excellent quality dress watches. Rolex DateJust or Daydate if you want to bring the bling. Stay away from the Timex and Casio G-shock types.