Probably none until I get bored. My computer sucks too much to have really "high quality" graphics or graphics mods, so I'm forced to keep it vanilla, pretty much.
The reason I got into KSP is from Robbaz, KING OF SWEDEN. But, on a serious note, I started out around 0.18 to 0.19 and beyond. I've been hooked since.
I think that it will eventually, and that is a BIG eventually. In my own opinion, I only like singleplayer games, so I'm not really that excited for MP in the way others are.
Honestly, I don't think that I would buy a DLC in any kind for KSP until there were a multitude or a bundle of them. As for the proposed realism DLC, probably not.
This isn't really a "build-in-orbit" station, but more of a single launch relay station. I had to attach a comsat to it because I forgot the all important antenna.