
These should be pretty self-explanatory. I can't remember how I found the Lum one, but I am particularly fond of it. I believe I bought the Kiki ones at the Animate in Ikebukuro, and I may have bought the Lum one there (or maybe the Nakano Broadway Building).
The LOTR one I bought at a Warner Mycal Movie theater when I went to go see the movie. (I had to wait FOUR MONTHS for that movie to come to Japan!)
The one with the bridge is the Akashi O-hashi bridge. This bridge is the longest suspension bridge in the world, connecting Akashi (just west of Kobe) to the island of Awaji in the Seto Inland Sea (Seto Naikai). There is a similar bridge that connects Awaji to Shikoku, but it isn't as long. Awaji Island was the epicenter of the great Hanshin Earthquake that decimated Kobe in 1995.
The Rose of Versailles ones came with the DVD box sets.
The Kaze Tachinu one is my most recent addition. I bought it at the Ghibli Donguri shop in Tokyo Station.