I am going to be installing SP 2013 Standard in a farm config. We'll have four servers: 2 WFE/App servers, 1 SQL Server, and one app server dedicated to Search. On the SQL server, I plan on 2-3 partitions, 1 for the OS and 1-2 for the logs and databases. I am not sure about the WFE/app server or the search server, though. Any guidance is appreciated.
For SQL Server:
1) 1 for OS(80GB), 1 for data files( size depend upon your data), 1 for log files
For WFE/App Server:
1) 1 for OS( 80GB) , 1 For the ULS Logs & IIS Logs ( because Logs chew all the space sometime, when enable the verbose and have operation going on),
The advice from Waqas is good, I also like to have a "Data" drive (where I store site collection backups, and other exports). This allows me to have a backup drive that is different from the Logs and the OS drive.