Do you like to keep a list of books you read? I started doing this some years back in order to make trips to the bookstore and library more productive. I wish I had started 20 years ago! I use a simple MSWord document with all entries alphabetical by author. Here are two sample entries:

Freedman, JF - 96House of Smoke-ok; 91Against the Wind; 98TheDisappearance-ok-unrealistic; 97KeyWitness+++; 00Above the Law+ 01Birds Eye View+

Friedman, Philip – Reasonable Doubt++; Grand Jury+; 92Inadmissable Evidence+;

At some point I started adding the publication date in front of the title so that I could tell the sequence of the stories, especially if the book was part of a series. My rating system was pretty simple:
+++ Fantastic book, A
++ Great book, A
+ Good book, B
ok All right book, C, probably wouldn't get another by this author
skip Poor book, F

If I read a book I really liked, I would sometimes look up the other titles in the series, and list them in bold. These would be books to borrow/buy.

Today I discovered that you can use one of several online resources to get even better mileage on your "list." You can get all the details in a blogpost by Timothy Broder. He describes and compares the pros and cons on three services:

My Library (Google)
Shelfari
Library Thing

All three are new and wonderful discoveries for me! Thanks Timothy!