Every home that I go into that I think is well decorated, it's not about matching furniture or anything of the sort. It's about people decorating their house to reflect their interests and their hobbies. My friends who are huge readers have their bookshelves as the most prominent part of their layout. One of my friends is super huge into video games, so he has two entertainment centers with about 10 consoles divided between them. My wife and I personally are huge fans of cars and antiques. When we finally get our own place and can get all of our stuff out of a storage room and actually put on display, we hope to incorporate them into our decorating. Truth be told, we don't have a lot of matching furniture, but I think it'll actually blend in well with the mish-mash of stuff that we have.
This is sort of what I'm doing, but due to a pretty low interest in decorating, I haven't made much progress. I have a huge stack of posters I'd like to hang. Mostly ones from concerts. I have a few of the more meaningful ones framed, and some time I need to sit down and figure out which ones coordinate well and start filling up walls. I'd also like to have some prints done with some of my hiking pictures. I've had one canvas print made, and I think it looks great. These will probably go in the more public rooms, and the music ones will go in my bedroom and the bathrooms. Like you said, they're based on my hobbies. They're pictures I took or they're bands I like/concerts I attended.