Based on whatever information we have had so far about the Windows 8 Consumer Preview that is going to be released at the end of this month, we can compare it with the Windows 8 Developer Preview, the build that is already out.
To begin with, the 'Start' button may not be present in the Consumer Preview. When you take your cursor toward the bottom left of your screen, you will be able to switch between the Metro User Interface and the desktop.
Microsoft preferred to retain the Windows 7 desktop icons in the case of the Windows 8 Developer Preview. However, the Consumer Preview will have a few Metro-style icons.
The division of the Apps list in the case of the Windows 8 Consumer Preview has not been done alphabetically. Instead, the segregation is done on the basis of categories.
The remaining differences can be spotted once the Windows 8 Consumer Preview is released later this month on the 29th.