Originally Posted by shuffling
When you install Windows 7, it creates two partitions. One is the primary partition (C), which is the file system you're familiar with when you use your computer. The 100 MB partition (E) is the system reserve, which I think is used by Windows 7 for some features that require a boot process separate from Windows 7, but I'm not entirely sure.
If you're doing a clean install, just delete both of those partitions, and install Windows 7 on a new partition using all of the available space.
The 100 MB partition was created by your previous windows install.
When faced with this choice, I would create a ca. 100 GB partition and use that partition to install WIN7. The 100 MB system partition will be automatially created.
The remaining disk space will be another partition. Use the 100Gb partition for Operating System and software.
Use the other partition for your personal data: pictures, movies, music, documents etc.
I think it is a good idea to keep OS and data separated.