While I don't have near a 55" chest, I can't bear having so much as a necklace on me-- a chest strap would drive me mad. I've been using a Mio Link wristband HRM, and love it. I don't even notice it's on my arm most of the time. Battery is only good for about 4 days of riding between charges (and I'm horrible at remembering to charge it) so I actually own two.

Bonus, any of the wrist-based HRMs are both ANT+ and Bluetooth.