Probably one of the greatest things I discovered when I got my first decent PC and got into computer stuff was of course free porn, then P2P, then MAME. I remember reading about it in a small article in EGM magazine. I thought "Wow I can play old arcade games on my PC? Awesome!" Then I discovered that older consoles that I loved as a kid like the NES, Super NES, and Sega Genesis had emulation programs for Windows and I could play my favorite old games all in one place. To this day I can still spend hours playing old Mario and Zelda games on my laptop. Recently I've started connecting my TV to my laptop via HDMI. Playing Super Mario Bros. 3 on a Samsung LED is good stuff. I use emulators for the previous consoles named plus Game Boy Advance, PSX, and old DOS games. The compatibility for some of the programs isn't always perfect, but it's better than paying $400 for a like new copy of Suikoden II on eBay to play on my PS3.
Yeah, there's the questionable legality of it, but so what? Emulation provides a unique way to play that you didn't have back then. Save states are probably the greatest function of an emulator. Need to go do something but don't want to lose your progress? Just press the Save State button and come back anytime you want, and pick up right where you left off. Then there's the issue of hardware breakdown. Your old NES is going to quit eventually, but with emulation you can load your programs, ROMs, and save files onto a USB stick and play them on any computer. There's lots of old 2D games I'll play long after I stop caring about FPS's and modern RPGs.
Another aspect is ROM hacking. You can play the original Mario or Zelda with whole new levels. There's even fanmade remakes for classic games. I just discovered a 16-bit remake of the original Donkey Kong called Classic Kong. There's also fan translations. There's many old RPGs for SNES that never made it to the US, but through emulation and fan translation patches, that's not a problem.
With smartphones and tablet PCs becoming more powerful, there's excellent emulators being released for Android and iOS. Emulation is the main reason I preordered the Ouya. Having all my old games in a more portable unit that easily hooks up to my TV is a very engaging thought. So whether you like your old games on a PC screen, on your TV, or on your phone, there's always an option for you.
Now, back to Dragon Quest VI...