For me it would be PS1. So many great RPGs and the start of the Metal Gear Solid series would have been great to experience when it first came out in my opinion. Instead I had an N64 which was equally amazing but man I wish I had a PS1 back in the day.
Really...nothing I've had an NES, SNES, had one of the Sega consoles at some point, N64, PS1, Xbox, XBox 360, PS3 everything before the NES era while nostalgic did not age well at all I feel like I've had one of the best gaming journeys just because of my starting point. Yes I skipped the PS2 and Gamecube but I have gone back and played all the fantastic games I missed except for a few PS2 gems.
dreamcast for sure. I still need to get jet set radio for xbox to fill those childhood nostalgic desires. The only real experience I got to have for dream cast would be those hour play sessions at the local target :P tons of soul calibur, looked amazing, and a few minutes of jet set radio when I got the chance but theyd hardly put it in.
oh and the once a month when the local after school group would rent one to play. Hydro thunder was amazing on that thing. Loved to play ready 2 rumble as well
My first game system was during the 16-bit era. I knew I wanted a game system, but didn't really know the differences between a Genesis / SNES. My parents went to a Best Buy and they talked them into a Genesis.
Granted, the Genesis is a fucking awesome console, and I had a lot of great memories on it, but I can't help but feel a bit deprived of what is arguably the best system ever.
I wish I played more good Dreamcast games. I bought one near the end of its life (for $70, no less), and proceeded to play the Sonic Adventure games.
And that was pretty much it, until I picked up a used copy of Shenmue a few years later.
But in retrospect, I really wish I had bought some stuff like Chu Chu Rocket, Power Stone (1 & 2), Typing of the Dead, or even Seaman. Those game were crazy. Games like that aren't made anymore (well, there's still stuff kinda like Power Stone, but that's beside the point).
I got an N64 for Christmas...IN 2001!
It was my brother's fault. We had the choice between a GCN or an N64 and some other stuff. Despite the fact that I now own 3 Gamecubes and many things besides, I still resent that little bastard for insisting on the N64.
The point is that I had an SNES until 2001, and an N64 until 2003 or so. I would really like those numbers to be adjusted to their appropriate positions.