If the everyday addiction isn't enough, I find the "Difficulty / Terrain" combo goal quite intriguing!! I just today reached my goal of 100 caches. I have used a GPSr for hunting and fishing for years, and just recently started geo-caching. I love my Garmin 60csx and have it loaded with Topo.
I think my new goal will be to see if I can get to 1000 by my one year anniversary. Oh ... and that "Difficulty / Terrain thing too.