I suspect one reason the look is so common is that many men don't own odd jackets. One might need suits for work, and one might have invested in some quality pieces, but men are less likely to drop real coin on cocktail party clothing. They're, obviously missing out, but I won't go so far as to say that suits without ties are wrong. Suits without ties have a place. As noted earlier, summer suits in poplin and linen can look quite nice without a tie. I often remember seeing this look at open houses for high school graduations. A wool suit can also work at places like jazz clubs, where only a minority of the patrons will have jackets to begin with.
As far as pulling off the look, once you've selected an appropriate setting, these would be my guidelines:
- The suit should have a slimmer, contemporary cut. I have a very nice MTM Golden Fleece sack suit, but it's the last suit I'd ever wear tieless. It looks like too much of a work suit.
- Steer clear of midnight navy and charcoal. Ligher blues and greys keep the outfit from looking too severe. The idea of wearing a suit sans tie is to convey casual sophistication. A nearly black suit would undermine that effect.
- Shirts should be solid blue or white, and suits should be solid or have a VERY subtle pattern. Some may disagree about this, but my feeling is that you've already decided to match your trousers and jacket, and to forgo the most interesting accessory that one wears with a suit--the tie. At this point, one shouldn't get cold feet. Go all the way, and embrace total simplicity.
- It goes without saying that the shirt collar needs to stand up properly.