I very well may be late to the game (this is technically yesterday's news), but if you hadn't seen it already, check out this gear review:
Short version: Garmin has a new watch available for pre-order with the optical heart rate sensor in the watch.
You know what that means! No chest strap! It's the lights that shine through the skin on your wrist.
I'm a big advocate of heart rate training, but oh, I hate the chest strap. I finally ditched mine in late December when I got a Mio heart rate monitor for Christmas. I wear it on my wrist and it's just a plain band (you can see it in one of the photos in the article I linked above, but here's a direct (non-affiliate ;) ) link, but mine is plain white) and it synchs with my Garmin, so I can see all my heart rate data on my watch as I run (just like I used to do with the chest strap).
And more good news: Garmin is using the Mio heart rate monitor. So I can attest to the fact that it works well!
It's been fun to feel like a cool kid not wearing a chest strap and having things on each wrist, but I guess whenever these start shipping, I'll be behind the times again since the cool kids will all have the 225.
Having something on each wrist hasn't really bothered me, but I have not run (or trained for) a full marathon yet this year. Usually in a marathon, I like to wear a pace band, and it may very well not work with the dual straps. I'll let you know in ... October?
Either way, I like my Mio and how it works with my Garmin enough that I won't be upgrading to the 225 anytime soon, but it sounds totally awesome for anyone who is in the market.