AWS Command Line Tool works much like boto and can be installed using sudo easy_install awscli or sudo pip install awscli
Once installed, you can then simply run:
aws s3 sync s3://mybucket .
download: s3://mybucket/test.txt to test.txt
download: s3://mybucket/test2.txt to test2.txt
This will download all of your files (one-way sync). It will not delete any existing files in your current directory (unless you specify --delete), and it won't change or delete any files on S3.
You can also do S3 bucket to S3 bucket, or local to S3 bucket sync.
Check out the documentation and other examples: