Are there anymore sites like 'del.icio.us' 'digg' 'swarmthe.com', where you can discover new sites? Maybe a site with millions of links to different kinds of sites in different catergorys, or maybe like 'swarmthe' showing all the most popular sites viewed each day. Thanks.

Del.icio like sites (http://www.google.com/search?hl=en&lr=&q=related:del.icio.us/)
Stumbleupon (http://www.stumbleupon.com/) is worth looking at as well.

Ow geez, you remind me of one of my former favorite sites whereby you picked a category and the biggest sites in that category were "fed" to me.

Of course these were paid entry sites and the idea has died.

You can, though, check the major web directories like dmoz, Google, alexa, etc. too. That will give you a good start... and especially Alexa, as it will give you sites in categories in order of popularity.