Everyone needs a .22 rifle. I think the Ruger 10-22 is top of the line for an inexpensive .22 (a little over $200).

I agree with the 22LR, good for plinking and small game. Almost any 22 will do the trick for you, but the more acurate rifles cost a bit more.

As and intermediate firearm, I suggest the 22 Hornet. It's a sweet round that you can reload for ( very simply ) and will take medium sized game and varmints.