The information included here does not cover all the amazing features of the two latest incarnations of Microsoft's operating system, but rather those that are pertinent to the maintenance, management and repair of hard drives and SSDs.
First off, Win7 and Vista offers excellent disk management features that should allow the average to advanced user to do all the necessary management functions without investing in additional software.
Users can, for instance: Create partitions, extend partitions, shrink partitions and lastly, delete partitions. These tools can be accessed by following this sequence of mouse clicks: Control Panel, Administrative Tools, Computer Management, Storage, Disk Management. Not all these capabilities were available in Windows XP.
The only drawback to these native tools is that they must be run from within Windows itself. It is often helpful to have a bootable CD with disk management capabilities, which may require purchasing a 3rd party program.
Windows 7 also supports TRIM for SSDs (see About SSDs for more information). It also has a Windows image backup function that creates a system image of your entire Windows installation. This is found in the Backup and Restore program under the Maintenance folder in the Start Menu. This is very valuable in the event that you must completely restore your system due to inability to boot the computer.
Also in Win7, in the aforementioned Maintenance folder you'll find the executable named Create System Repair Disk. This will allow you to prepare a bootable CD with startup repair and restore functions. If you have a Windows 7 installation Disk, you don't really need this, but most computers (including Vista and many XP PCs) don't come with a Windows CD nowadays.
For Windows Vista, which doesn't include the option to create a system disk, you can make one here.
Your XP, Vista or Win7 computer may have come with a recovery partition on the hard drive which you can enter by pressing a key shown on the screen at bootup. Unfortunately, these are limited to either a simple system restore (rolling back to a previous date) or to completely restoring Windows to it's original, off-the-shelf condition, so unless you have your data backed up somewhere you will lose it. Obviously, these options won't fix any physical or many logical hard drive issues, so creating a bootable System repair CD is still a good idea.