Color: The main four colours for suits worn in business are black, light grey, dark grey, and navy, either with or without patterns. In particular, grey flannel suiting has been worn very widely since the 1930s. In non-business settings or less-formal business contexts, brown is another important colour; olive also occurs. In summer, lighter shades, such as tan or cream, are popular.

Funny how the navy pinstripe and grey chalkstripe, once the staple of the gentleman's wardrobe, have now be absorbed by the business world to the extent that wearing either for leisure is considered inappropriate by many.
The plain charcoal, grey chalkstripe, plain navy and navy pinstripe are all acceptable for a gentleman's lounge suit, day or night. If there is any distinction, the grey chalkstripe is considered best worn during daylight hours so that its visual effect may be best appreciated. Source: Are there rules for suit colors at weddings?

Pleated front or flat-front: Pleats work well if you have larger thighs or if you carry extra weight low on your torso. One or two pleats can give a classic look to dress pants, but they can be too much on a slim man.

Slim-fit or wide-leg: It's not just a matter of fashion; different styles work better on different body types. Slender men will want to choose slim-fitting slacks, so they won't look like they're borrowing clothes from Dad. Men who are larger on top -- either with a belly or a muscular chest -- will want to choose wide-leg pants to balance their upper and lower halves.

Cuffs or no: Cuffed pants are definitely considered the dressier option when wearing a standard suit or the odd trouser, but black-tie tuxedo pants should always be without cuffs.
Cuffs are flattering on tall, lanky men.
Shorter men will look taller without cuffs.

One rule for pant cuffs says that flat-front pants should not have cuffs. Although this is not always true, the rule should be considered with caution. Flat front pants and cuffs clash because they are derived from different cultures. Flat front pants are considered to be a continental European tradition; Pleated fronts and cuffs are of Anglo-American origin. Although these may sound like obscure details, mixing these two styles is fairly obvious to well-dressed gentlemen and should be avoided.
Source Peter Beltaine

Cuffs on narrow pants will create either unsightly break(s) or a highwater effect.

Pant length:
The back should be 1 1/2" up the heel above the floor for a medium to full break.

From Andy Gilchrist's Encyclopedia of Men's Clothes, Trouser Chapter:
If you don't cuff your pants have the tailor slant the bottoms so that the hem is lower at the back to the top of the shoe heel. Tailors call this a "fishtail". Difference should be 3/4" - 1 1/4"
Nordstrom's will not do more than 1/2" because of the difficulty of slitting the fabric to get part folded under to sit flat against the trouser. Slitting also precludes lengthening if it ends up too short.
(Bloomingale's will do a slant cut)
Carlos Coto, a friend and the master tailor at Summit Tailors in New Jersey says, "you can make pants with slant cut to hem. It can go as far as you want them to be without looking ridiculous."

Slim cut, narrow pants, will have more break because they hit the shoe higher up.
The bottom of the trowser on my last suit (32" waist) was 9 1/2" across (when flat - 6" diameter) and the break was fine when it was cut with 1 1/2" at the heel; The suit I just got is 8 1/2" (5.4" diameter) and there was too much break (to my taste).
The back should be at the shoe heel, about 1" off the floor with the slant cut.

Cuffs are hemmed straight across, with the back around the top of the shoe heel so you get a full break.
Source: Cutting Trouser Cuffs on an Angle - Ask Andy FORUMS

The narrower the trouser, the more front rumple.

Break above
floor
at heel
Stature Style
Full 1-1.5" Tall Bold statement, contemporary, preferred by the working professional.
Medium 1 3/4 - 2" Medium height Conservative. Safe. Standard.
Characterized by one fold in the fabric when the cuff is resting on the shoe.
Short 2.5" Slender torso High fashion, tailored look with only a small crease.
Best with slim fitting suit.
Note A dress shoe is about 3 3/4 to 4" high at the heel and the sole is about 1", so the back will be near the sole for a full break and close to the top of the shoe in back for no break.

People with extra curvature of the back or big butts will also affect how the pant bottom sits without alteration of the rear.

Jackets:
Buttoning:
Single-breasted suit coats may be either fastened or unfastened. In two-button suits the bottom button is traditionally left unfastened except with certain unusual cuts of jacket.

When fastening a three-button suit, the middle button is fastened, and the top one sometimes, but the bottom is traditionally not designed to be (although in the past some jackets were cut so that it could be fastened without distorting the drape, this is not the case with current clothing)

Books:

Links:
Give Your Pants The Right Break | MensXP
The break: How to choose the best pants length + how to tell your tailor | The Effortless Gent
Proper Pant Length for Men | eHow.com
Summit Tailors in New Jersey
Men's Dress Pants Buying Guide | Overstock.com
Suit (clothing) - Wikipedia, the free encyclopedia
Wedding Day Fashion - AskMen

last updated 25 Sep 2011