PSO is a gap in my gaming background I really regret. It was pretty popular in my online circles when it came out, and I almost bought it when I saw it on store shelves, but my family was still running on dial-up then. I got the Xbox version as a Christmas present the year that came out, but I guess I didn't do my homework and didn't know there was a subscription fee to play online (on top of the Xbox Live subscription fee) so I ended up returning it.
I did play Phantasy Star Zero on the DS when that came out in 2009, but that was even more niche with an even smaller playerbase that didn't stick around so I only really beat the main story before shelving it.
https://backloggery.com/FridgeBeard
http://i.imgur.com/AW4vp.png - Credit: Breloom