Do you have a basic battery of guns already that includes a centerfire rifle, quality shotgun, defensive handgun and a well set-up .22? If not, I would look to the area you are deficient in. If you already have all those bases covered I would be thinking BBQ gun. For me that would be a HiPower or 1911. 451_Detonics has some spot on suggestions as well.
Good suggestions for a basic collection. For a graduation present I would "BBQ Gun" as well. Well, at least something to keep and remember my graduation. Evil black rifles and glocks/XDs just don't cut it for this type of situation. I own my share but they lack character. I am thinking something with wood. Maybe a nice Browning or Berretta shotgun, Kimber 1911, Smith Revolver, Browning HiPower, the list could just go on. Don't get me wrong I like my AR & Glock but I treasure my Red Label.