If you can't have both, I also vote for the 9MM carbine. Get something that does not use proprietary magazines if you can. There are several that use Glock magazines, so you are not forced to buy over priced, hard to find magazines. Fun to shoot and relatively cheap ammo.

I personally have a Kel-Tec, Gen 2, Sub 2K, in 9MM, Glock mags. I love it. I know there are Kel-Tec haters out there, most of whom are simply parroting what others have posted or said. I am not suggesting this is the gun for you. You need to look and decide for yourself. I do love my Sub 2K however.

I am also not too sure about your comment regarding ARs as being a good investment. I certainly wouldn't purchase one with that in mind.