had to pick one gun depends what i'm going to do. love my marlin model 60, and my marlin 883 (22 mag), ans sav. 110 in 25-06 to name a few. If i had to pick one it would probaly be the 22 mag just more usable than the 25-06.
Marlin 1895 XLR .45-70. It's a flame thrower, will take any beast in North America, and my wife bought it for me on a whim.( I might of left a couple magazines laying around opened to a picture of it)
One of my favorite all around fun guns to shoot is one of my M1 carbines. I just love the peep sights and the gun is light and just feels right. For something cheaper to shoot the 10-22 is hard to beat. My Savage MKII in 17M2 and my Kel-Tec SU22 are quickly moving up the list though.
I can't really pick just one so I'm gonna agree with Jack Ryan and say "One that is fully loaded and in my hands."