ok there are 2 points of view what happens if my mobile gets stolen

1. mine: i trace that ***** down until i have it and then god sake, let me have a good day before

2. the guy who stole it: run fast, run really fast. this n900 means more for the owner than his own life. be aware that this phone is a trap if you only think about turning it one (in case you did turn it off)

Around here, phone popularity has a lot to do with what would get stolen. I've NEVER seen another N900 and I live near Chicago. You know what I do see? iphones, Droids, EVOs... thats the stuff that gets stolen.
Thieves steal things that are valuable, but common, so they can sell it easily. Thieves busted into my friend's car and they stole his ipod nano. He had a $1,000+ camera lens in its branded case in the backseat... it was still there when he got back.
But if I was stealing a phone, the first thing I would do is to pull the battery.

I would remote detonate the 100 grams of C4 I rigged inside the phone.

If my phone was stolen...

Depending on the circumstances I'd feel miserable at myself for allowing such a situation to occur.

Then I would buy a new one. : )

To save my phone from such situation I use GPS tracking system for my cell phone. If it got stolen then I can track it.

Here's supposedly 3 ounces, that's about 85 grams of C4:
http://www.youtube.com/watch?v=d0j_nKYV73I

Considering that the stolen phone would likely be in the delinquent' pocket, a smaller amount would suffice. No point in making our dear phone too much heavier than it already is ;>

If my phone was stolen, I'd cry.
To avoid such, I simply don't trust people at all; I always keep the phone in zip inside-pocket and never let it out of my sight. If I'm in a public place, I usually use a bluetooth handsfree (BH-215, works nicely) to avoid exposing my phone unnecessarily.

I would feel bad, reeeealy bad, if my N900 was stolen. Luckily my phone is barely exposed, and little people actually know that i have a N900.
Also, if my phone was stolen, i would have to use N73 again. That's A PAIN after 6 months with N900.

I'm personally not worried about my phone being stolen; I'm more worried about forgetting it somewhere.

But, I've got a similar setup to you; I have a 24/7 openvpn/UDP connection active, and can SSH in from anywhere, as well as a few scripts that dump out relevant info like battery status, GPS position, etc.

If I couldn't locate it precisely, I'd remotely crank up the volume and play a recording: "Help! I'm lost! Please press the button on the phone to call the owner for a cash reward!" or something.. and run a simple X app that calls a number when a button is pressed.

Well, first off, I'd bite the the muggers ear off, then I'd let him get away with the phone.
Next I call my mates. When they arrive, we all go into the nearest bar and I shout “I've just been mugged. Has anyone got a mobile phone?”
And the first tw@t that jumps up and shouts “I've got one 'ere mate” is the target.