I regret not digging more into domain names when I was younger. I registered my first domain in 1998, when I was 14 years old, and between that time and 2006, I had 10-12 domain related projects.
In 2002 I was fishing for some LLL.com domains, all I looked up was taken (of course) so I gave up, instead of searching for quality keyword domains, I believe I could get some decent names for a reg fee at the time.