Here is another gem :http://allth.at/home/welcome
You enter a few terms that you want to search, tell them where you want them to search, then go off to your work or to bed. come back later and find it nicely ranked and listed.
Custom search made fresh for you *after* you told them what you want to look for.
And, I tried, it is awwwwwwessssommmmmmeeeeeeeee!
All this started with grokker.com, IIRC.
They came up with this non-linear search and semantic search and stuff.
It still looks pretty good.