We had to do one as part of our outreach (story of DH and cyncie type thing for birthfamily). It turned out to be a lot of fun and even though I had to comb through so many old pics and write some narrative I am so glad I spent the time. I ordered one for us and one for DH's parents too. They LOVE it! Like you, I am hooked and I plan to do one for some vacations we took and one for our baby boy ... of course I have to get a little more sleep and find an extra hour in my days but I WILL do it. We used IPhoto but I have seen a couple of books done on Shutterfly and I like that format better.
I wholeheartedly second this recommendation for a fun, relatively easy and very special keepsake.