Below is the standard I follow when configuring drives for servers, it helps structure files for future management if needed. The below includes drives for running a SQL Server too.
C – OS and system level files. Only
D – Program files for all apps (including SQL Server)
S – Instance level files/SQL Server system databases and log files typically (except for TempDB) (note.. If I have multiple instances, I won’t make 4 of these.. I’d put all SQL binaries for all instances on S in most situations, with the folders providing the separation)
F – Data files for user databases
L – Log file drive for user databases
T – TempDB
X – Backup drive (though in a lot of cases I elect to stream a backup across to a network drive, not paying for a copy after the backup and I’m immediately backing up to storage someplace else.)