A few thoughts to add:
1) a .22lr will kill someone, but compared to other handgun rounds, the terminal ballistics suck
2) 9mm is really cheap
3) Both the Glock 17 and Springfield XD are nice guns
Personally, what I would do is buy a 1911 Style .45acp, kimber/springfield/S&W whatever you like and can afford, and then grab a .22lr conversion kit for it. That way you can practice with cheapo .22 and work your way up to .45 by practicing good shooting habits. The gun also then doubles as a far more serious weapon if you want it to be.
1) a .22lr will kill someone, but compared to other handgun rounds, the terminal ballistics suck
2) 9mm is really cheap
3) Both the Glock 17 and Springfield XD are nice guns
Personally, what I would do is buy a 1911 Style .45acp, kimber/springfield/S&W whatever you like and can afford, and then grab a .22lr conversion kit for it. That way you can practice with cheapo .22 and work your way up to .45 by practicing good shooting habits. The gun also then doubles as a far more serious weapon if you want it to be.