Running out of space on C drive?

I have a 50GB C drive partition with the standard tools Visual Studio, SQL Server etc installed on my Vista. I would run out of space once in a while in C drive eventhough my installed software wouldn't account more than 7 GB. How to find culprit? Windows doesn't make it easy to identify the folders consuming the most storage space. But, there are tools out there. I used Windirstat to dig deeper. It's a great tool and open source. So, no worries of malware.

1) Ran the Windirstat. Got this awesome split of storage crunchers by type and location. It displays the max consumptions by list of file types and this gorgeous motherboard look-alike graphic pinpointing to the specific files. Here is a snapshot.

2) Winsxs folder was the primary culprit with 10GB of space. You can find out why Winsxs takes space and what's in it by reading this thread. Other culprits were SQL Server DB transaction logs, PDB files, SVN-BASE files
3) To reduce the size of Winsxs (only if you have Vista with SP1 installed), run the "vsp1cln" from cmd prompt and say 'yes' to permanently install SP1. This will remove the ton of SP1 backups leftover in Winsxs.
4) To reduce the SQL Server Transaction logs(mine being a dev machine..logs are waste of storage), read this thread and this fix. I changed the recovery model to Simple and ran DBCC SHRINKFILE on the log files. Also, there were few old log files that probably never got deleted with gigs of space. Got rid of them as well!
5) And, PDB files need to deleted as and when they get created. I don't see any other option for developer machines.

Hope this helps!