PDMARSH  I've used this for years, up through MacOS X 10.5.8 and it's worked great. However, with the owner silent for so long, I have to assume we won't be getting a 10.6 version any time soon. I also use iStat and they have a similar product called iStat menus that they say they ARE working on a version for 10.6, so you may want to give it a look.  
(Version 1.3)

PDMARSH  I saw that Hardware Monitor had been updated to version 4.5 and decided to try it again. Although version 4.3 clearly didn't like my original aluminum iMac, version 4.5 works perfectly for me now.

I'm now running MacOS X 10.5.2, and my original aluminum 24" iMac 2.8GHz machine has since been replaced by Apple when it was damaged during a repair, so I don't know whether it was a system software update, a hardware update, or the updated Hardware Monitor software, but my Mac's been running 24x7 for a week now with the new version with no issues.

So, I must say this issue is now closed for me.  
(Version 4.5)

PDMARSH  Well, it's been a couple of months since I turned off Hardware Monitor and I've had NO MORE FREEZES, so this closes this issue out for me.

Hardware Monitor is a cool app, but clearly has a problem with my new iMac's 2.8GHz Core 2 Duo processor.  
(Version 4.3)

PDMARSH  I migrated my old G5 Tower apps/accounts/data to my new 24" 2.8GHz iMac in early November, and had periodic freezes (from 5 minutes to 3 days) that I was having trouble resolving. To narrow the field of issues, I built a clean partition with Leopard on the iMac and proceeded to install my old apps and data just to use as a control environment.

I found that this control environment NEVER froze, so I knew I wasn't having a hardware issue, but my migrated account continued to spontaneously freeze periodically. To see what was happening, I turned off the screen saver and energy saver, left the CPU always on, opened the Console log and Activity Monitor window (selected highest CPU usage column), left iTunes running, and waited.

The next time it froze, I looked at the Console log on screen and noted nothing usual was happening when it froze. Activity Monitor showed the iMac was idling at ~6%. Interestingly, I was able to connect ONCE to the iMac from another Mac and play an iTunes song, but multiple selections failed, and then the iMac became unresponsive over the network.

I read on a forum of another user who was having sporadic freezes and thought Hardware Monitor might be involved, but he couldn't confirm it. When I rebooted from my control startup partition, I noted that I hadn't yet installed Hardware Monitor on it, so I thought I'd try turning it off on my migrated startup volume.

That was nearly four days ago, and the iMac has remained fully operational and functional.

I initially tried just turning off the enhanced sensors extension, but that didn't help. My iMac ONLY remained stable with Hardware Monitor turned off.

Since it takes anywhere from 5 minutes to multiple days for the freeze to occur, it's difficult to diagnose, but I intend to reactivate all my usual stuff (except for Hardware Monitor) later today, install the pending Apple updates, reboot, and wait some more. If it freezes again, WITHOUT Hardware Monitor running, I'll be sure to update this post. But, it's never survived more than three days before, and it'll be four days this afternoon.

I should note I've been using Hardware Monitor for years, and it works just fine on all my PPC Macs (all also running Leopard). But it definitely appears to be having an issue with my new iMac.  
(Version 4.3)

PDMARSH  CoconutBattery no longer works on my PowerBook G4 1.67GHz Mac running Leopard (MacOS X 10.5).

It runs, but displays nonsense battery cycle counts and battery power levels.  
(Version 2.5.1)

PDMARSH  I've been using Thinking Home for years since I like automating lights around my house, but this product has never been updated to work properly with a USB Serial Adapter, like the Keyspan USA-28, with MacOS X. In the past it has generally worked, but I always winced when starting the application because more often than not it would not see the X-10 Interface (a CM-11 or IBM Home Director) plugged in six inches down the line.

Finally, today I replaced my old G4 iMac (lampshade) with a newer G5 iMac and Thinking Home refuses to see the active serial ports installed via the Keyspan Serial Adapter software. I've visited the Thinking Home site, but all they do is blame MacOS X and make a suggestion to unselect the active ports in the Network Port Configurations panel.

So, in a nutshell, this worked pretty well with MacOS 9, but has been very problematic with MacOS X.

I've been transitioning to Indigo, talking to real USB devices with assigned addresses, and it works much more reliably, and recommend it to others thinking about home automation.

I no longer recommend Thinking Home software.  
(Version 1.1.7)