What is the maximum upload file size accepted by SharePoint 2010?
Each Web Application By default have 50MB for one time attachment to be uploaded. You can modify it from:
Central Admin -> Manage Application -> Select your web application -> General Setting -> Set Max Upload Size
If file size is too large then you should also update
executionTimeOut (Increase this time from IIS Setting) value and
ConnectionTimeout (Update this time from web application web.config file) value.
As in 2007 you can specify it.
This article in technet is a quite good read, it talks about digital asset management on SharePoint 2010 and how you should plan things ahead: