I think I'll never get bored enough to put all my books in Excell... Too much of them. Half of the flat is filled with books. There was a character in one of Soviet kid's books, Znaika (Know-it-all), he had books "on the shelfs, on the floor, on the tables, on the chairs and even on the bed" - it's a good description of my apartment. Most of them are fiction easy-reading, several hundreeds on history, some old science books from college etc. And I have a corner at work where I store about a cubic meter of classics...
My Father has even more books... And he has a collection of about 5000 records, some as old as 1910s. He has a perforated card catalogue for most of them...