If you
- Have a web server with MySQL and PHP
- Read sites that have RSS feeds on a semi-regular basis
- Ever use different computers, or can't find a desktop aggregator you like...
The only notes I have: Do use the auto-subscribe bookmarklet. Don't forget to set up a cron job to update the feeds. Don't forget to htpasswd protect the directory -- every link you click will have your FoF install as the Referrer URL.
I think the thing I like best about having an aggregator is that I can happily subscribe to infrequently updating sites cough cough like this one and I just get to see all the updates when they hit my browser. Subscribing to a weblog no longer means having to troll it (in)frequently for updates that might not be coming.