Mosin M44 and M38. I've got a Russian M44 that had the bayonet ground off and was refinished at the arsenal, thereby turning it into a defacto M38. It's got all the great qualities of a Mosin, the flawless reliability and robust build quality, cheap ammo, etc. But it's far lighter and better balanced to the point of actually being a practical rifle for real world use. And that short barrel results in a lot of noise and flash with surplus ammo which makes it even more fun. The boom and 2ft+ fireball that shoots out the muzzle even in broad daylight is enough to gather a crowd of onlookers at the range.
I'm also one of those weird people for which the Mosin is ergonomically favorable, and that combined with the manageable but noticeable recoil means I can shoot hundreds of rounds at a range session and not get tired of it, or even lose the grin off my face.
Not only is that little Mosin my favorite milsurp, it's my favorite firearm in my collection(around 20 firearms)and never misses a range day.