Well, You should buy a Minigun. tons of fun and you can mow down weeds with it. I think the last transferable one sold for roughly $108,000. There ya go. You need to buy that.
Now, here is how this is going to work. People are going to chime in here with their favorite pet gun. You will hear from the CZ fanboys, the 1911 fanboys, the fudds, the tacticool group and the glock fanboys.
After they all get done telling you about their particular favorite, your choice will be... Every single gun ever made. So, how would you make a choice?
So, since the minigun is a "fun" gun, that is my suggestion. Hope it helps.
Or.... you could buy what you want, or at least give us an idea of what you like....