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#131
It depends on whether you want to keep the Recovery and Tools partition, or wipe the slate clean to have the full disk for just Win7. If you choose the latter be sure to make your Recovery Disks and save a Win7 backup image so you have a path back to where you are now.
If you want to keep Recovery and Tools then I'd keep System, otherwise delete all partitions and create new ones as you wish, or just click Next to let the installer create one partition and format for you.