Devices

I have a Bodybugg. You were armband with it on it (it goes on the left upper arm). I love it. It measures how many calories you burn. You can wear it for up to 23hrs a day however I take mine off while I sleep. The hard part is remembering to charge it and there is no instant gratification. You have to hook it up to the computer to see how many calories you burned (although I think there is a newer model with an instant read gadget). I just wished MFP linked up to it.
Hope you find something that works for you.

I have a fitbit Ultra and a Polar RCX5 with GPS. The fitbit is great for keeping track of your general activity and it also can monitor your sleep, something I find useful as sleep is not an easy one for me and improving it is a large part of my wanting to loose weight. I also have a sleeptracker but find the fitbit software so much easier and more reliable to use. The fitbit helps me know how active I have been and also shows when I have slipped.

The Polar RCX5 is total overkill for my exercise level and activities but I do like my gadgets and personally I am really driven by having the feedback on how I am doing. It wirelessly syncs to polars website and plots out the routes I have walked and also maps out the heartrates during activities. I find the feedback on how much to do each day useful and I can do the same routine again later and compare the recordings.

As gadgets go I also love my wireless withings scales as they take care of recording my weight and uploading it to MFP and fitbit. I find having these bits done automatically great as it is when I am slipping that I need the feedback most, but these are the times I am least likely to do it manually.

I do like gadgets and so some of these may be to fidly for someone who just wants the basics and likes their gadgets to sit in the background.

P.S.
Forgot about your comment on wrist/chest straps. The fitbit clips to your belt, though when I have wanted it out of the way and to avoid catching it I have found works fine clipped to underwear. Though I dont know how well it would cope with being fallen on.

I have and use a BodyMedia and love it.

I love my gadgets as well. For general monitoring I have a bodymedia, but I'm probably going to replace it with a Fitbit. Fitbit does all the same things that the bodymedia does, and I don't have to pay a monthly subscription. I'm doing a training program for a sprint distance triathlon so I have a bunch of gadgets to monitoring my performance. For my swimming I have a Garmin Swim, my biking I have a Garmin Edge 500, and for my running I have a Garmin Forerunner 410. I have a footpod and HRM to use with the FR, the Edge uses the HRM as well, and the Cadence sensor I have attached to the bike. I also have a Withings WiFi Scale as well as their Blood Pressure Monitor. Like I said I love my gadgets.

You can pick up the fitbit on amazon for about $90.

Just purchased a Polar FT7. heard so many good things about them and guess what, it is true. Calories Im burning is amazing compared to relying on MFP or the machines at the gym.