PS2 is certainly a high-point in retro gaming via emulation. The huge, diverse game library spanning >10 years, a great emulator in PCSX2 and tons of community mods and HD texture packs make it amazing.

You've got the option of OG authenticity with CRT emulation (although I use a shader emulating a high-end analog RGB CRT so the effect is more subtle) or you can 'upgrade' games to looking and feeling quite modern yet without the modern cruft. Also want to give a nod to PS3 / X360 emulation as both have come a long way in the last ~18 months and I'm really enjoying working my way through a backlog of titles I never played back in the day.