PS2PSXe is your one and only option if you are after PSX hardware or games on your PlayStation 2. While there were a few different attempts to emulate PSX on PlayStation 2, PS2PSXe is the only emulator that has actually managed to do a good job. The emulator is not the best though, but it gets the job done. It might feel a little slow at times – accuracy was the primary goal of the developers. However, it can handle most games out there. You can now enjoy Final Fantasy VII, Metal Gear Solid, Castlevania: Symphony of the Night or Crash Team Racing without too much hassle.
PS2PSXe is available for free and does not come with too many requirements. While it perfectly replicates old school games, its interface is not super intuitive, so newbies might struggle a little. Fortunately, there are lots of tutorials and instructions over the Internet.