After the SP1 release of SharePoint 2010, product team changes offcially the boundaries limits of SharePoint.

You can consult all this new limits in the "SharePoint Server 2010 capacity management: Software boundaries and limits" page on MSDN here:

http://technet.microsoft.com/en-us/library/cc262787.aspx

One of the most important thing is the new recommandation about the size limit of the content databases:

Limit

Maximum value

Limit type

Notes

Content database size
  (general usage scenarios)

200 GB per content database

Supported

We strongly recommended
  limiting the size of content databases to 200 GB, except when the
  circumstances in the following rows in this table apply.

If you are using Remote BLOB
  Storage (RBS), the total volume of remote BLOB storage and metadata in the
  content database must not exceed this limit.

Content database size (all
  usage scenarios)

4 TB per content database

Supported

Content databases of up to 4
  TB are supported when the following requirements are met:

  •   Disk sub-system performance  of 0.25 IOPs per GB. 2 IIOPs per GB is recommended for optimal performance.
  •   You must have developed plans for high availability, disaster recovery, future capacity, and performance
      testing.

You should also carefully
  consider the following factors:

  •   Requirements for backup and
      restore may not be met by the native SharePoint Server 2010 backup for
      content databases larger than 200 GB. It is recommended to evaluate and test
      SharePoint Server 2010 backup and alternative backup solutions to determine
      the best solution for your specific environment.
  •   It is strongly recommended to
      have proactive skilled administrator management of the SharePoint Server 2010
      and SQL Server installations.
  •   The complexity of
      customizations and configurations on SharePoint Server 2010 may necessitate
      refactoring (or splitting) of data into multiple content databases. Seek
      advice from a skilled professional architect and perform testing to determine
      the optimum content database size for your implementation. Examples of
      complexity may include custom code deployments, use of more than 20 columns
      in property promotion, or features listed as not to be used in the over 4 TB
      section below.
  •   Refactoring of site
      collections allows for scale out of a SharePoint Server 2010 implementation
      across multiple content databases. This permits SharePoint Server 2010
      implementations to scale indefinitely. This refactoring will be easier and
      faster when content databases are less than 200 GB.
  •   It is suggested that for ease
      of backup and restore that individual site collections within a content
      database be limited to 100 GB. For more information, see Site
      collection limits    .

For more information on
  SharePoint Server 2010 data size planning, see Storage and SQL Server capacity planning and
  configuration (SharePoint Server 2010).

                
     Important:
   

Content databases of over 4
    TB, except for use in document archive scenarios (described in the row
    below), are not recommended. Upgrading of site collections within these
    content databases is likely to be very difficult and time consuming.

   

It is strongly recommended
    that you scale out across multiple content databases, rather than exceed 4
    TB of data in a single content database.