I would get a .22 because it is cheap to shoot. Buck Mark Browning or a Ruger. Both will last forever and the nod goes to the Browning for ease of cleaning.

Then I would get a 9mm because it is plenty of gun with good loads and you can get practice loads for cheap. For the pistol itself I would go Glock or M&P but there are alot of solid choices. You can not talk me out of a Ruger or Browning .22 though.