Go for the cheapest name brand one you can find. The chest strap fails and they end up being the cost of another crappy set. All the features you need is average heart rate, max heart rate and real time heart rate.
I have gone through several and swore I would only buy cheap ones like Reebok or Polar close outs. Try cycling stores online like Nashbar.com
Sigma Sport PC14 Heart Rate Monitor
$35.00