ISO Recorder v3 captures ISO images into "C:\Users\%username%\AppData\Local\VirtualStore\Windows\System32\".
I've used ISO Recorder v3 for some time now to burn iso files onto CD's and DVD's. It's simple, fast, and free, and I've been a very happy user.
Today I needed to make four copies of a DVD - videos and photos captured from my family's recent holiday, and I decided to use ISO Recorder. Right-click on the DVD, choose "Create image from CD", and name the file to copy to. Simple.
Of course, once it was finished, I then wanted to burn that .iso to my DVD. The only problem was.... I couldn't find it. Desktop? User directory? Application directory? Um, Temp directory? Nada. I tried to capture a second copy of the ISO into a well known location (root of my C: drive, perhaps), but found that the user interface didn't let me specify a location for the file - just a name.
After a 15 minute (automated) search, the file turned up in "C:\Users\egirard\AppData\Local\VirtualStore\Windows\System32\Cottage2009.iso" - and once I found it I was able to easily burn my copies. I'm using Vista, and I expect that other operating systems (XP, etc) would find the file in "C:\Windows\System32". So for anyone else out there whe can't find their ISO, hope this helps you.
And by the way, I'm still a happy ISO Recorder v3 user.