45 ACP might be my favorite cartridge. You'll love it in a revolver- as stated, moon clips are cheap and make for quick reloads at the range- plus you don't have to chase your brass if you reload. I don't, but I save the brass for a friend who does.

It may be due to location, but I have not had the good fortune to find a 1917 for $500. There is one on consignment at a LGS marked $650 with rubber grips and it's been there for about 2 years, though.

I will echo what Stake Out said- I love the history of my 1917s, but I had the opportunity to shoot a 625 once and it was SUPERB. Not sure which dash number it was, but it was a 5".

Start combing the usual online sites and see what they bring and make your decision there.