What's the limit for "insertrecords" and "updaterecords"?

What's the limit for "insertrecords" and "updaterecords"?

I'm planning my application to create a number of leads, accounts, contacts and events each day.  Given the API limit of 250 / per user, I want to send these through in batches.

Does anybody know the theoretical and practical limits for "insertrecords" for leads, accounts, contacts and events/activities?

Thanks