3 is my favourite game in the series. I absolutely hated how it started when I first played through, but once it got going and I got the hang of some of the mechanics, it just clicked. The story is great, the bosses are interesting, the setting is cool. It just hits all the right notes.
Used PS3 is really a great system right now, most of them can be soft modded to play ps1-3 games, and you can install any size sata drive you want!
I have a ps2 but the upscaling isn’t as good as having a system that has hdmi on it and upscales itself.