what is the best data format to start with when importing data into mysql?

[Emiliano Rustighini]

hi all. 
I need to import data into a mysql db that will contain around 1 million
records.
The DB where the data are contained originally is in a building connected by
internet to the web server in a server farm.
The data should be updated batch once a day.
I can ask for the data in any data format, but I would like to get some
advice on what is best to ask for.
If you have some suggestions about the connection tool as well it would be
grand.
 
thank you
Emiliano