I believe that the notification light actually stops blinking after a while and not blink indefinitely.
Today was my first full day of work (and not playing with it all day long like on Friday). I was in and out of my cube all day and just checked to see if my LED was blinking. It wasn't....but later when I came back and actually unlocked the phone, I had missed a whole bunch of messages!
I decided to send myself and e-mail from work...it arrived on my phone...LED was blinking...and I just left it there. Came back to my cube about 30-45 minutes later...and the LED stopped, but the e-mail was still waiting in the notification bar.