CopySiteIsEasy, is a site copier tool which allows you to download index file with its css and js locally. For entire site download you can use httrack. Normally whole site will going to take upto 100 mb and that's alot for our server, i'm constantly working on this site and soon make feature like download 50 mb files for free.
Why not whole site
As i told earlier, normal blog take upto 250mb and we run this service for free, downloading and packing it in zip take alot bandwidth and server resources, you can download httrack software it gives you so many cool feature especially local saving.
Feature coming soon
Scrap 50 mb for free is my first priority adding soon within few weeks and second, download archive content feature.