I currently have 22 semi-automatic .22 LR rifles:
Colt Stagecoach carbine
Marlin 60SS (x2)
Mossberg 715T (x3)
Remington 66 (x5)
Ruger 10/22 (x8)
Winchester 290 (X3)
Plus 5 semi-automatic .22 MAG rifles:
Kodiak 260
Remington 597 (x2)
Ruger 10/22M (x2)
To use "as is", without spending any additional $$, I'd recommend looking at the Marlin 60SS as they are both rugged and reliable.
If you're looking to spend additional $$ to personalize it for your specific wants/needs, I'd recommend looking at the Ruger 10/22 as they are the small block Chevy of the rimfire rifle universe in terms of after-market parts.