One of my Windows Vista computers is an old Media Center PC that has a built-in USB multi-card reader, that is, slots on the front for SD, CF, SM and MS memory cards. This means that when I open Computer Management and use Disk List or Graphical View, I see four additional drive letters in use (F G H and I) even though I hardly ever use these slots. Here's how you can get rid of these drive letters and also make it easier to access memory cards when you insert them in the slots.
Open Windows Explorer and create a folder named "mem" or something similar in the root of your C: drive. Then create subfolders named SD, CF, SM and MS beneath the C:\mem folder.
Now open Computer Management, right-click on F: drive (for example) in Graphical View and select Change Drive Letter And Paths from the shortcut menu. Click the Add button, select Mount In The Following Empty NTFS Folder, click Browse, and browse to select C:\mem\SD (for example). Click OK, select drive letter F: and click Remove.
You've now removed the F: drive mapping from this USB device and added C:\mem\SD as a mount point instead. Repeat the above step for each of your remaining memory card slots.
Now when you need have memory cards in these slots you can easily access their contents from the command line, or you can create shortcuts on your desktop to each of these mounted folders if you prefer.
If you have feedback concerning this tip, I'd love to hear from you.