Look over
this thread -- some pics of my space and toys, and some other peoples' as well.
I'm going to make a spanking bench in the next couple months, I'll post images of that too once it's done.
As for important furniture, I suggest getting a bed that you can be tied to: there are a lot of possibilities from that position, and it's a toy that can be used for longer periods. I made our with several hooks around the base, and no upright posts to get in the way, but any sturdy bed with convenient spots for locking subs to is good. The other starter I'd suggest is a st andrews cross; they're VERY easy to make and, how I made them -- with removable bolts in the center -- very easy to break down and store.
Enjoy, and please share whatever you come up with!