All of the original consoles have decent multi-cart support these days. It's absolutely worth it. The only console I haven't been able to find a easy and viable option for is the Atari 5200. There's a cart out there, but it's not that easy to work with.
I own pretty much every common gaming console and handheld from the Atari 2600 to PS3. Nearly every one of them has some kind of flash storage or hard drive solution engaged, meaning no more collecting carts/discs. And for that I'm happy. I neither care nor have the space to hoard all of the individual games.
The below photo is old, but a close representation of my setup. I've added a dozen more system since this photo was taken, and I'm now using two CRT TV's on both the left and right sides for gun game systems. There's a very complicated rats nest of wiring on the back side, and a set of instructions on how to switch video/audio for various systems. Center display is a plasma with both component and HDMI inputs, but the Onkyo receiver does most of the heavy lifting
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