If you don't like having two devices on your handlebars, take a look at a combo unit. Performance has the Vetta V100HR (has been on sale for $70.00) that does speed, distance, cadence, and heart rate. Does time in, above, below, averages for each, and total workout time average.
Great little computer for $70.00 - or ever more. I have been using mine for about 3 a month and love it.