Shoutbox

If they are on the same network, activate Home Sharing and just transfer each library [Music, Movies, Apps...], but this won't maintain your folder scheme if you don't use iTunes' default.

Or you can do what M73A suggested. You can get your Library file, it's an .xml, it will be in iTunes, a folder inside your media folder [check in Edit > Preferences > Advanced > iTunes Media Folder location]. It updates everytime you change something inside iTunes, from listening to anything to closing it, so just look for the most recent iTunes Music Library.xml.
[It's called music Library but it also includes all your other media, except Apps.]
If you plan to use the exact same directory, the partition has to have been assigned the same letter as the partition that used to hold your old library:

• Open iTunes, set the media folder to the same directory as your old one, close iTunes
  
• Copy your whole iTunes media folder to the same location on your new computer, and let Windows replace every file
  
• Open iTunes

If you plan to use a different directory:

• Open iTunes, set the new media folder, close iTunes
  
• Copy your whole iTunes media folder to the new directory in the new computer
  
• Open your library on your new computer and use "Replace" to change every reference to your old media folder directory to the net one [each file and each library has a "<key>Location</key><string>file://localhost/[media folder]/[Kind/file]</string>" line], then save it
  
• Open iTunes

If any of your media files had DRM, you have to authorize your new iTunes with the Apple ID you used [after you finished transfering your library].
If your old apps don't reappear, just use Store > Check for available downloads after authorizing your new iTunes.