Re: 22 mag vs 22 hornet
Either the .22 mag or .22 Hornet will serve you well depending on whether you want a rimfire or centerfire. However, personally, I prefer a comparable .17 to a .22 because they've generally been more accurate for me. What .17 caliber are you comparing the .22 mag and .22 Hornet to? There are many factory rounds in rimfire and center fire that are good options and, except for the new .17 WSM, have been around for awhile. There are more options for the reloader. The .17 HMR and .17 WSM are rimfires and cartridges like the the .17 Hornady Hornet and .17 Remington Fireball are centerfires. All are flat-shooting and generally very accurate in factory guns and ammo.
If you reload, there is huge advantage to going to a centerfire because you can load heavier bullets and/or other powders like Trail Boss for reduced velocity, less meat damage, and less noise. You'll also be able to load your own rounds when you need them rather than being at the mercy of the stores for factory ammo.
The older I get, the stronger gravity becomes.