I find that I've become a bit anal about downloading all my runs, and almost feel naked if I don't run with it. However, and coincidentally, someone said to me last night to at least try one race without the watch to see if it concentrates my mind simply on the act of running, rather than worrying about the watch all the time.
What I think the Garmins are brilliant for is the advanced training workouts... Unlike you, I find it difficult to assess my pace and how far I've run, so in that sense my watch has revolutionised my training.