Yeah! I decided to take the safety course on a whim about 2 years ago now and I've been loving riding ever since. It's been a fun challenge learning to ride skillfully. I still own my first bike, which is a Honda CB900F 919. It's been great to me.
That GS500 looks nice. I don't know if you've looked at them at all, but the Suzuki SV650 is also a good midsized bike that is supposed to be a little more forgiving on beginners. They're usually fairly ubiquitous on Craigslist, too. I was looking at them for a while before I bought my 919.
Also, if you're looking for a good online retailer for gear and whatnot, I can't recommend Revzilla.com enough. They do great video walkthroughs of pretty much every popular piece of gear that they sell. Super helpful. Though I'll say that buying a helmet is one you'll definitely want to do in person. Go into a motorcycle specific shop and ask them to help you find one that fits your head. It's a lot more nuanced than you'd think, and getting a good fit is vitally important. I suffered for a while wearing my first helmet, a Scorpion EXO-500, that was too round for my oval head and put pressure on my forehead. I ended up buying a nice Arai Signet-Q with custom cheek pads a while back and it's been much more enjoyable riding with a helmet that fits me.
Let us know when you buy your bike!