I own at least about 50 but have yet to get to them all lol...
BTW here are some things you can do with your domains:
- build a full-fledged site or blog with them
- use them as parked domain monetized with adsense or other
- let them sit, age an then sell them
- use them to redirect to your other sites
- use them to mask you affiliate links
- create tons of sub-domains with them
I'm sure there's something I left so feel free to add to it!