Taken from The New Oxford American Dictionary, this is my favorite entry at the moment. I actually wrote it out and carried it around with me for a while, but sadly I lost that scrap of paper.
concise, laconic, pithy, succinct, terse
If you don’t like to mice words, you’ll make every effort to be concise in both your writing and speaking, which means to remove all superfluous details (a concise summary of everything that happened).
Succinct is very close in meaning to concise, although it emphasizes compression and compactness in addition to brevity (succinct instructions for what to do in an emergency)
If you’re laconic, you are brief to the point of being curt, brusque, or even uncommunicative (his laconic reply left many questions unanswered).
Terse can also mean clipped or abrupt (a terse command), but it usually connotes something that is both concise and polished (a terse style of writing that was much admired).
A pithy statement is not only succinct but full of substance and meaning (a pithy argument that no one could counter).