OK I will answer the question about maxxi images, when you use NTFS file compression it will compress the image down to a few megs but this is "size on disk!" it wont show up in explorer (it will still show full image size since the compression works behind the scene. and will appear under total free)
http://img236.imageshack.us/img236/853/clip28gb1mf.jpg
http://img236.imageshack.us/img236/5739/clip5fk5mn.jpg
take a look at "Free Space" on my drive properties see how it changes from 74.1 GB (uncompressed) to 75.9 GB (compressed)
I think people get confused cause the file wont appear like ziping or raring.
http://img236.imageshack.us/img236/846/clip41gr.jpg (uncompressed)
http://img236.imageshack.us/img236/6186/clip57gm.jpg (compressed)
as you see the file size won't change like a zip or rar would, but overall disk space will be increased as compression is transparent.
also i should note people with ntfs cluster size above 8k (8024 bytes) (the default is 4k (4024 bytes)) wont be able to use NTFS compression also people with older filesystesm such as FAT32/16.
The reason maxxi images are so large is the game usally check the file sizes or sectors across the image so the file has to be the same size as the original most of the time the images are all filled with 0's (this is why it compresses so well) besides for the very end of the image that usally holds the table of contents (TOC) so you can still see the file structure when you mount the image, and the mds file has the protection sectors locations in it and other info.
Also you DON'T need to reboot to free the space after you compress it will happen as soon as the os finnishes compressing it (varys depending on speed of your hard drive(s)) usally F5 will update the window to show most accurate data.