Do I really need to keep .LDF files?
You shouldn't delete the log file.  If you are trying to reattach a data file without the log, SQL Server can technically recreate it, but there are a few potential issues, like if there were open transactions when the database was detached.  In which case, you'd have total data loss.

Consume the space, and don't delete your log files.  You're asking for trouble with that.

See this article on Transaction Logs, in particular the "Log Mismanagement" portion.