I am a total fanboy for Ascent, an amazing running and biking tracker for the Mac. It syncs with just about any GPS, including my Garmin 305, and provides more detail than any one person should need.
I guess I feel a bit guilty in saying that running for me can be very much about the numbers — it’s great to see pace per mile in a race or look at total miles for any given week. I’ve tried keeping a running journal on paper, but the comment field in Ascent. Take a look at the screenshot — there are two reactions I can imagine: some will say “you’re freakin’ nuts, who would want all that detail?” and others will say “how can I buy this thing? Like right now.”