I have other free apps on the Market but here, I'm going to describe how I used my home monitoring/security apps on my G1.
First, the "DSC Alarm Monitor" allows me to turn on/off the home alarm remotely. I can also check on the status of all 8 zones remotely. To make it easy to use, the app is configured only once. Launching the app instances connects to my house so I can make a quick check or change.
If the alarm is triggered, the alarm system calls my cell phone where I can check on the sensors and then look at my cameras.
I have 6 cameras surrounding the house which I can view remotely with my G1. Again, to make it quick and easy to use, I configure the cameras once only. When launched, the cameras show up in a gallery style display so I can thumb throw them.
Finger gestures (flings) trigger pan/tilt and pressing keys activate presets (although response is slow most of the time due to network). I use panasonic cameras (because my dlinks died) but the app supports Sony, Axis, Panasonic, Linksys, Airlink, Trendnet, Vivotek and more.
Finally, I have the Pachube Viewer app which most people can't figure out. Here's some background to hopefully clarify it's purpose. I have an Arduino with an ethernet port and custom sensors (think of it has a micro-computer with lots of sensors and a mini web server). It runs 24/7 collecting sensor data which is polled by a logging server. All this in 12k bytes of code!
The Pachube Viewer allows me to view the current sensor readings as well as a 24 hour history graph on my G1 again without having to log in or use a clunky browser. I wrote the app so that it can display any data feed so I released it on the Market.
The running theme is that I want NATIVE apps that make my tasks easy/fast. You can all of the above using a browser but who wants to hit urls, login, navigate on a little screen, etc... I need it now. I need to make a quick change. I need to go... I think more apps will show up on the Market that helps users to more remotely and do it faster.
Since all the apps launch without a password prompt, I protect the phone with the built-in pattern password system. I hope you find these apps useful as well.