Try this website for excellent deals on flights!
http://www.kayak.co.uk/
(absolutely hassle free)

formatting C# for html
http://www.manoli.net/csharpformat/

syntax highlighter
http://code.google.com/p/syntaxhighlighter/wiki/Languages

Videos on how to do most things:
http://www.wonderhowto.com/

Picking colours for web development etc:
http://www.colorjack.com/studio/

Free Regex tool
http://www.ultrapico.com/ExpressoDownload.htm

Heathrow Airport arrivals/departures Info
http://www.heathrow-airport-guide.co.uk/flight-arrivals.html

old versions of certain applications
http://www.oldapps.com

QR codes (2D barcode generator)
http://www.qrstuff.com/