Memory Monitor displays an LED meter on the taskbar notification area (system tray) that shows a rough percentage of memory use. Click for more detailed memory-usage information. Helpful for detecting applications that allocate memory but do not free it.
Simple executable which doesn't require installation (nor can it be installed), clean design which intends to display both total and free amounts of both total physical and virtual memory (which happened to be all I wanted). Also, it didn't crash.
Cons
The graph would be a little unimpressive (a visually weak little line graph apparently), if it worked (mine was totally blank). Worst of all, it fails to calculate the memory values correctly (not even close), or erroneously lists them as 0.00MB.
Summary
The situation. Given 4GB physical memory (3838MB actual), with 2500MB used, leaving 1338 MB free, as well as 9773MB total virtual memory with 3082MB used, leaving 6691MB free...
The response. This program indicated: Total Physical Memory was "minus" 263.69MB and Free Physical Memory of 1222.62 (varying, perhaps properly), which it calculated to be something around 464% free (well over 100% free; rather impossible). As for the Virtual Memory, this merely displayed 0.00MB for both Total and Free, which figured to be 100% free.
Essentially the program in it's current state is unusable due to erroneous and useless output.<br /><br /><span class='notifyMsg'> Updated </span>on Aug 23, 2010<p/>Addendum: A couple of final points.
Apparently the program was also supposed to display an "LED meter on the taskbar"; alas, no such item appeared.
Lastly, I should note that this was on Vista x64, and while it indicates Vista compatibility, nevertheless, the 64-bit aspect might just possibly play a part in or be the source of some or all of the errors.