Perhaps the most interesting katakana expressions I found were the subject headings for the あさひしんぶん Online, which is the online version of a major Japanese newspaper. Though the website is entirely in Japanese (there are separate foreign language editions), the headings for each of the individuals topics were essentially all English words written in katakana. They include ウォーキング (Working), ブック (Book)、トラベル (Travel), カルチャー (Culture), and シネマ (Cinema). Obviously, there are Japanese words for all of these things, but the decision to write them as English loanwords in katakana suggests a very conscious choice on the part of the newspaper. As one of the textbook excerpts noted, katakana is often used as a way of appearing cosmopolitan and global, which seems to be the intent here. By writing their subject headings in katakana-ized English, they can give the impression of writing on more global topics and appealing to a more global audience. Because English is quickly becoming the universal world language, it seems like Japanese newspapers and similar organizations can take advantage of that fact by anglicizing what they choose to write. Of course, they do not want to completely take away the Japanese aspect of the paper because that would be a disservice to their readers. Instead, they are taking part in a movement towards the use of English as a worldwide lingua franca but still keeping it within the confines of their language by using katakana. The Japanese writing system is rooted in centuries of tradition and uniqueness, and so writers would not simply want to begin using only rōmaji. Using katakana-ized English that retains the essence of Japanese script and pronunciation while introducing readers to these new, exotic, and potentially very useful words creates a nice balance between traditional Japanese culture and the influx of western and English ideas.
The other interesting word I found was バイキング, a word which means "buffet" in Japanese. Phonetically it sounds like the English word "Viking," and it does have that meaning in Japanese as well. However, as 浜田先生 told me, most Japanese people would first think of a buffet if they heard that word. Apparently the origin of this term used to describe a buffet stems from a restaurant called the Imperial Viking, located in the Imperial Hotel in Tokyo. (Source at bottom) This restaurant was the first in Japan to serve buffet-style, all-you-can-eat meals. This particular term is an excellent example of the reinvention of foreign loanwords and their new applications within the context of Japanese culture.
I think each textbook had a different manner of explaining katakana due to the different viewpoints, interests, and intentions of any given textbook author. Most of the textbooks were similar in their description of katakana as a syllabary used to write loanwords, onomatopoeia, and words an author chooses to emphasize. The textbook that stood out was the one that also emphasized the more cultural aspect of katakana and its use in Japanese printed material to seem more cosmopolitan and sophisticated. As I found in the Asahi Shimbun Online and as I saw first-hand in Tokyo, it is true that even when a completely suitable Japanese word exists, many times people consciously decide to write in katakana-ized English or another foreign language. I think that the last textbook was the most comprehensive and interesting in its manner of explaining katakana because it went into greater depth regarding the cultural applications of katakana. While it is completely sufficient to say that katakana is used in loanwords and onomatopoeia, explaining more about how and when those loanwords will appear gives readers of Japanese a better idea of what to expect when they read printed material in Japanese.
*Source regarding origin of バイキング
http://www.fnetravel.com/english/tokyohotels/imperial.html
このしゃしんは、東京とちょうしゃ (Tokyo Metropolitan Government Building) のながめ (view)です。東京のビルは、たかいですね！
東京こくりつきんだいびじゅつかん (Tokyo National Museum of Modern Art)。とてもおもしろいえがたくさんあります。
よこはまのちゅうかがい (Yokohama Chinatown) です。アジアの中でいちばんおおきちゅうおかがいです。中国のレストランやみせがあります。
