The Master System is definitely my favorite Sega console... right before the Mega Drive.
Here's my small collection of Master System stuff. It's nothing impressive but it's a collection nonetheless.
I hope to get a Sega Mark III in the future as I really want to get into collecting Sega SG-1000 games, and the Mark III is backwards compatible with the cartridges!
I also have some Game Gear stuff, like games in original boxes and whatnot.
But really, do you guys want to see that? The Game Gear is easily my least favorite gaming machine Sega put out so I don't think any of it's worth sharing.