The N900 is far to heavy to hang from a Zephyr HXM heart rate monitor. I wish there were a nice Zephyr compatible heart rate graphing app along with perhaps altitude and speed.

I have been looking for a nice rainproof predator type wrist/arm pouch that wasn't made from that fake leather stuff which I expect to tear inside a few weeks. Currently I just stick my N900 in a shorts pocket.

I use my N900 for long range cycling and running to track heart rate like a tachometer so I don't red-line myself and get too exhausted as well as keeping in the target zone on the stationary bike stand in winter. On the road I use BH-214 stereo multimedia clip on headset which has a 3.5mm headset jack. I like Sygic Mobile Maps 10 for navigation and wish that EOL'd for Maemo5 app had a HRM display.