Only you can determine what is best for you as we have no idea of your hand size, recoil sensitivity, preference for a 1911 type grip angle or Glock, desire for manual safety, etc.. However in your price range you should also look at the M&P line as they are more ergonomically designed. My cousin loves his Ruger SR9 that he bought for $400 for range use. It has been 100% reliable and will outlive him. For plinking I use my .22's and even then at today's prices it is no longer cheap to shoot a .22 lr. These days 9mm can run you almost a dollar a round so if you are a first time shooter and not going to carry you may want to consider a .22 instead and get the 9mm later. And yes, once you get one gun you will get others (assuming you like to shoot. If not, your gun will collect dust and it will not matter what you buy) no matter what you think.
My last two new shooter students both stated that they could only afford one gun and it had to last them for a long time and agonized over their choices. Eight months later and they both own 3 guns now. As for the Glock 19, it is a good gun. Reliable, simple to use, disassemble and a good defensive tool. Whether it fits your hand and is the best for you however, is a personal decision. As I tell my new shooters, do not let others decide what gun you should buy. You do not do that when you buy a car or clothes or most other things so do not do that with your guns. Research, try if possible and form your own opinions. DO NOT buy a gun you never held in your hand. I know too many people who order guns and then hate them because the grip is too big, gun is too heavy, slide too hard to rack, difficult to disassemble, etc.. Good luck in your quest.
One last word of advice. If you really want a more expensive gun, save up for it rather than settle. I know many guys who did not buy the gun they really wanted because it was a few hundred more and ended up spending a lot more money buying several less expensive guns and ended up with several guns that cost a heck of a lot more than what they really wanted and are still not happy. I think that many of us have been there before. For some it is a mental thing where they cannot see spending a $1000 on a gun but buy $600 guns one after the other because none of them is like the $1000 gun they want. I see this all the time and was that way myself. Heck, I am still paying off guns that I no longer own. Now I just buy the gun I really want and it is actually cheaper in the long run.
