This is perfect when you are looking back over a season for trends and highs/lows. If you get injured or are ill you can also put in notes to remind you what you took, what treatment etc. All this can be hugely valuable when trying to work out how to improve the following year. On that note, this year also includes the ability to compare directly with 2004 if you kept the data. You should be able to copy/paste straight out of the summary section of the 2004 training log!
Distances can be in either km/miles but should be consistent to make the comparisons and totals meaningful. You can get the log from this web page: http://www.tri-force.org/training_log.html
The bad news is I've picked up a cold and a cough. After last weeks blowout travel week that wrecked my training, I only got in a brief swim on Tuesday, the travel on Thursday from San Diego to Chicago and then New York, the freezing temps. and the Saturday trip back to the UK and being trapped with all those germ ridden people has finally got to me. I guess some easy spin sessions this week is the best I can expect. D'oh.