I am in week 8 of a C25K, and my ultimate goal is the Disney Princess Half in 2011. As a birthday present for myself and a prize for finishing my C25K, I am looking at the Garmin 205 and 305. They appear to be the same, except the 305 has a heart rate monitor. Even though I am new to running, I have exercised for years, and I have never used a heart rate monitor. Is it worth the extra $$ (it's a $20 difference on amazon). Will I want to use it in my training? Any opinions on these products? The reviews seem to be good, but I would love to hear from any of you who have one. Thanks so much!