Of course, this question depends on a bunch of things like (a) how much money do you already have invested, and (b) how old are you, just to name two. Since you are in your twenties and you already own an NSX, I'll tell you what I now wish I had done had this amount landed in my lap when I was in my twenties, assuming that I already was making a reasonably comfortable living but wasn't already incredibly wealthy. I would invest it - invest the whole thing. Just put it away in a good investment and let it grow over the years. If you feel you must "treat yourself" to something, spend $5K on something you'd enjoy - mods, vacation, whatever - but still invest the remaining 90 percent of it.
Incidentally, I hear that most financial advisors, when asked what they would advise someone who won the lottery, respond that the person could spend 5-10 percent of it on things they always wanted but should invest 90-95 percent of it.
[This message has been edited by nsxtasy (edited 11 March 2001).]