Need website suggestions for a URL index I'm building.

Hello everybody! 

I've posted about wanting to create a search engine before, and so this post may sound a little bit redundant, but I would seriously love to get some input on what goes into the R&D of a custom search engine I'm looking into building.

This engine will initially be similar to that of YAHOO! from the early 90s, when it was still a human-edited index of websites without crawlers...(though I likely will add a crawler/crawlers in the future...)

Basically, I'd like to get started early on storing sites for the engine for processing and whatnot.

I'd obviously start out with the most common sites...but still would love input. lol

I'm open to any and all suggestions as long as they're not explicit! :)