I started with SNES because it is fairly common, has great games, and is very popular. Other good consoles to start with would be Dreamcast, N64, or Atari 2600.
I would always choose a general computer like the one you have. You can play old games on that, including the sidescrollers made for old consoles. Quake is a terrific title for the general computer.
Okay, then I have a huge collection of N64 games that I still keep. I know that certain games have more value than others, like StarFox64, Mario Kart 64, and Super Mario 64 since they were the first of that system. I'm hoping that they'll gain some value in the upcoming years .
If you plan on getting PS1 games then you can just get a PS2 if you have difficulty acquiring a good PS1 as the PS2 plays PS1 games plus you'll then have access to two game libraries to choose from. Nintendo 64 is also a good system with plenty of great games to choose from.