I use Turtle wax to wash off the bike, but I don't soak it in water; just lots of soapy suds 8)
I then just dry it off with a microfibre cloth and use Mr Sheen to shine it up.
I do also use a bit of GT85 as well to clean the drivetrain, then once dry, lube it up with 'purple extreme.'
I did use Fenwicks once after a mate lent me some and that was really good, brought all the dirt off in what seemed like seconds.
It was that good though, I was a bit worried about using it all the time and if there would be any issues with it affecting the finish etc.