Arduino Resources on the Internet
There are many people just like you in the Arduino community who are trying to do different things with their Arduinos. Mostly people just engage with projects that interest them. All research, including trying to find a good major project, begins with asking yourself, "what have others done in this area". Here's some sites that have interested me lately. Have a look and create your own three sites that involve one of these: a site for cool Arduino projects, an educational site where the Arduino is used and a book about the Arduino. Add a little bit about each site so the rest of us get your opinion about what it is and what you think of it.
Makezine is cool
The Babuino project for Brazilian kids.
Check out the el-cheapo robot.