Use the following links to report phishing attempts, scams, abuse, etc. Please let me know if you are aware of others that should be added to the list.

PhishTank (operated by OpenDNS) is a great resource. You can redirect your phishy emails to them as well as the companies below.
https://www.phishtank.com/add_web_phish.php
Redirect phishing emails to: phish@phishtank.com

Apple
http://www.apple.com/uk/legal/more-resources/phishing/

Google
https://www.google.com/safebrowsing/report_phish/
https://www.google.com/safebrowsing/report_badware/
https://support.google.com/mail/contact/abuse

Amazon: stop-spoofing@amazon.com
Apple: reportphishing@apple.com
Facebook: phish@fb.com
FedEx: abuse@fedex.com
Linkedin: phishing@linkedin.com
Netflix: phishing@netflix.com
Paypal: spoof@paypal.co.uk
Salesforce: security@salesforce.com
Stripe: support@stripe.com
Wells Fargo: reportphish@wellsfargo.com

Government UK
HMRC: phishing@hmrc.gsi.gov.uk
Information Commissioner: https://ico.org.uk/concerns/marketing/spam-emails/
Police: https://reportlite.actionfraud.police.uk

Other
decentsecurity.com
https://www.spamcop.net/
spamgrabber.org