The first project I intend to take to completion is a laser tag pack and scoring system. If this is your first project (as it is mine) I would recommend breaking everything down into learning how to activate/deactivate/read/write etc different components first.
For instance, first I learned how to use LEDs, how to turn them on and off, how to use the PWM outputs to make RGB LEDs and regular LEDs pulse. Now I'm learning how to make infrared TX and RX in the manner that I want. I apologize if that is way below what you already know, but seriously, you have to learn how all the parts work before you get in over your head and find yourself not completing the project you want.
There are tons of resources available here and around the web. Good Luck! (Also, here's a really good place to get started: http://www.ladyada.net/learn/arduino/index.html)
Like I said, if you're way past that, my apologies.