In order to make room, you have to get rid of one of your consoles (we'll stick with consoles for now). This assumes you have more than one, which most of us do. This includes all games and accessories.
Which would it be?
I have:
CV
2600
5200
7800
NES
Intellivision.
This is a tough one. An obvious choice would be the 2600, since the 7800 plays most 2600 games. But that's MOST games, not all. Some of the better ones I cannot get running on a 7800.
The CV is obviously going nowhere, and- contrary to what some at Atari Age might think- neither is the 5200 (there's just something about it that captures a good era in gaming). Besides, I've put far too much work into the thing!!
I also like the Intellivision, even though it's been years.
Really, then, it's either the 7800 or the NES. The NES has Elevator Action, Galaga, Gauntlet, and others, but the 7800 has Food Fight, Dig Dug, Joust, Xevious (I prefer the last two to the NES), and such.
So, for me, though it's close, it would be the NES. Although I would consider the 2600, so it's not 100%. Hey- now that I'm posting this, it's a really tough question. So if you can't fully decide, I'm sure in no position to say anything!