I already did this and it's the bootable HDD that I created that I am using for the re-install.
It won't install without authorising my mac online. If I allow it to authorise online, it then goes into a downloading screen where it's getting additional components 76 hours it will take (internet is around 120Kbps).
Can I avoid the download part?
I've ended up restoringa time machine backup i made on the day i got the machine, which is just as good i guess.
Apple has gone to a pure cloud-based install. If you don't have fast internet (or internet at all), you have to do what you did, or make a clone with one of the cloning programs.
People have also mentioned various ways to make an installer disk, but I don't know if that will alleviate the download of updated components.
Here's the most popular, it seems: http://blog.gete.net/lion-diskmaker-us/