Well the first thing that happens when that door opens for me is the smell. Is her smell of her place pleasant, nasty etc. Personally my sense of smell is one of my greatest assets, and ooo it's a big turn on for me if I smell something that is very pleasant (no need to go overboard with the perfume here ladies).

As for seeing things, the obvious one would be how clean/messy it is. I'm not a neat freak myself but as long as it looks like it belongs where it is i'm fine with that. I'm a very functional oriented guy, so mismatched things don't really bother me.

Upon entering her room I look where her bed is, (does it have room for 2? heheh j/k) but another big thing is jewelry, whether it's layed out or boxed etc. Tells me a lot about her, whether she's a "princess" on the inside or not. After that, photos of family, friends, ex's etc. as they often are great conversation starters and tell me what she did to her ex's lol.