Back in the Compuserve days, a writer named Wanda Swenson gave me advice on what she called her "infoindex." It was a plain old Word file. She used one for her work as an author to track URLs, references, files, and so on, and one at home to track her insurance policies, medical records, etc.
Basically, she just dumped everything into it along with the keywords she thought she would need to access it later.
For loose pieces of paper, she put a number on them and put them into a single file (really big file). When she wanted to find something, she'd enter the search words into Word, and eventually find what she was after. If it had a number, she looked in the file. If it was a book, she'd entered its shelf location. If it was a file, she had its cabinet and drawer number.
I've implemented forms of this at various times and various jobs. There's a lot to be said for ease of data entry and quick searching (plus you can print it out and take it with you). But if you need to do complex searches or really need the power of a database, then it may not meet your requirements.