What is the culture neutral dateformat for SQL Server
I recommend reading Tibor Karaszi's The ultimate guide to the datetime datatypes.
If you input your date/time in unseparated or ISO 8601 format, then you should be fine with any configuration.
Unseparated = 'yyyymmdd hh:mm:ss'
ISO 8601 = 'yyyy-mm-ddThh:mm:ss'
Update (from comments):
If you need to enter a date only (without the time part), then you have to use the 'YYYYMMDD'
format, as 'YYYY-MM-DD'
will not work. See the linked article for an example.