Depends on its use and your particular style. I mention this because what you intend to use it for (interviewing, up-scale social, day-to-day business etc.) along with the crowd it will be seen in (conservative business, politicos, venture business, brandy tasting with buffy and kip etc.) really determine what works best.
For me, dark blue or black (depending on the quality of material, black looks bad when it is cheap IMHO), high cut, three button. Goes with just about anything and flexible enough that I can modify the look for whatever group I need to mingle in. Perhaps a bit too serious for certain functions, but I usually don't mind looking a little harsher, more down to business than everyone else. About the only flaw is that you can't really dress down with it (though I prefer just to ditch the jacket on those days).
Then again, my old boss always described my business clothing style as "noir hitman" which works for me... but probably isn't for everyone.
Overall, though, don't sweat it too much. Get what you can afford and what you're comfortable in. In the long run I doubt it will make THAT much difference in your life.