If you're in Command Prompt:

diskpart

then

list volume

sample output:

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     E                       DVD-ROM         0 B  No Media
  Volume 1         System Rese  NTFS   Partition    100 MB  Healthy    System
  Volume 2     C   System       NTFS   Partition     99 GB  Healthy    Boot
  Volume 3     F   Data (local  NTFS   Partition    365 GB  Healthy

and finally

exit

to return to the command line.

For the sake of completeness, there is yet another way:

fsutil fsinfo drives

which returns:

Drives: C:\ D:\ E:\ F:\

(Not a very scripting-friendly output, but it may be useful for human eye)

Some reference. That should work since win2k but only with Administrator account.

(Thanks @Carlos Campderrós for enhancing the answer)

If you're using powershell then you can type in

get-psdrive -psprovider filesystem

Edited in response to comments to only show filesystems

wmic logicaldisk get volumename,name

You can get (query) multiple properties this way.  This will give you the partition/drive letter and the label you gave the drive/partition when you formatted the drive:

Name  VolumeName
C:    OS
D:    Data
E:    Programs

For help and to list all the permission options:

wmic logicaldisk /?

then

wmic logicaldisk get /?

Use the doskey built in function to create an alias that runs the wmic command with the necessary atributes

doskey v=wmic logicaldisk get caption

This will create an aliases "v" that whenever typed will run the given command and list all volume letters.

To see available drives and their mount points from the cli I use

mountvol

You can also use the unmounted volume GUID for some commands like chkdsk and stuff.

When you're using powershell, you can use the simple command

get-volume

and get a nice list with 8 columns:

DriveLetter Label FileSystem DriveType Health OperStatus FreeSpace Size

I write Label where get-volume writes FriendlyName (and I have abbreviated some of the titles in the list in order to minimize the risk of scrolling horizontally to see the end of the line).

In VBscript we can use:

Dim fso,colDrives,objDrive
Set fso = CreateObject("Scripting.FileSystemObject")
Set colDrives = fso.Drives
For Each objDrive in colDrives
  Wscript.Echo "Drive letter: " & objDrive.DriveLetter
Next

In Powershell you can list drives inside an array with:

$drives=gdr -psp FileSystem|select -eXp root

Here it selects root property which shows like C:\ where name shows like C.

To iterate over drives in batch you can use:

@echo off
for /f "tokens=2 delims==" %%a in ('wmic logicalDisk get caption /format:List ^| find /I "caption"') do (
  echo %%~a is your drive letter
  echo Do what you like here
)

my approach would be a batch file with a standalone single command, (not external command needed)...

echo Available Drives:
for %%v in (A B C D E F G H I J K L M N O P Q R S T U V W X Y Z) do if exist "%%v:\\" echo %%v:

I absolutely love the pure batch method shown in the answer from cybercontroler, all internal commands no less!

I wanted to share my batch edit/modification that based on cybercontroler's answer.

For my current project, I needed to identify which drive labeled as DATA so I replaced the echo command with vol (internal command).

I also used the set command to create the variable [1] that would contain the full set of capital letters in order to shorten the for command's length.

Since if exist will be checking for drive letters only, there will never be a space character in this test, so I omitted the double quotes.

Testing the omission the two back slashes yields the same results.

The added command line @echo off filtered the output to show results only.

I piped the results to the external find command to filter serial number lines created by the vol command.

I placed a pause command so that it wouldn't be necessary to run a "Command Prompt" beforehand in order to see the results when clicking on the batch file.

The results from the original identified all available drive letters mixed in with for command processing the full set of capital letters. With @echo off filtering, my run displayed:

C:
D:

The results using vol displays: Volume in drive C is OS

 Volume in drive D is DATA
Press any key to continue . . . 

Here's my batch file which includes both for commands; you can comment-out the for command that you do not want to run by prefixing command lines with two colons (::).

Batch File

echo Available Drives:
for %%v in (A B C D E F G H I J K L M N O P Q R S T U V W X Y Z) do if exist "%%v:\\" 

echo %%-:
@echo off
set [1]=A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
for %%- in (%[1]%) do if exist %%-: vol %%-: | find "in drive"
pause

Note that this batch method does not identify DVD drives, not sure why. But the command fsutil fsinfo drives does. My output reads: Drives: C:\ D;\ J:\ (J:\ being my DVD drive.)