As we've said before, SP1 won't bring many (if any) visible changes to the average user. In addition to rolling up previously available updates, Windows 7 SP1 introduces some key virtualization and remote desktop improvements.
Subscribers may want to wait until the initial rush subsides -- Microsoft's servers typically get slammed hard when top-tier downloads become available. Otherwise, we recommend downloading with the Akamai downloader. It's working well for us at the moment.