N64 for sure.

It has to be the N64, though I'm not sure if Nintendo would prioritize it over adding N64 games to the Switch online service. They have to give "value" to the service, after all...

Psone mini is a failure. I Have all others, but don't have psone mini.  I have the Neo Geo mini ( horrible)

I Want a Dreamcast, Sega Saturn and N64 asap.

Dreamcast
Most of the ones I like on the list I still ownN64, Game cube, PS2

N64.

So much potential classics to include, it'd be great. This time around, N64 would be more successful than PS.
N64, I'd say, would probably also be the newest console you can do this with; the games of consoles after it will probably be too big (in MB's I mean) and they'd have to include bigger, more expensive storage capacities.

None. No reason to pay for a more expensive, and simultaneously more limited emulator.

A properly emulated Saturn with a lot of Panzer Dragoon and those ported arcade games would be pretty cool, methinks.

I have to go Saturn, as so many of the game are expensive and/or hard to find. A mini system with Guardian Heroes, Shining Force, Astal, NiGHTS, Panzer Dragoon, and more would be pretty sweet.

N64 after that, and then Dreamcast.

For a new one, either N64 or PS2. I do wish Sony redeem their minis, though, and come out with a PSOne mini with more games, better emulation, and Dual Shock controllers. Even if they still use an open source emulator, have it updatable.

The Master System. Love that console.