Altavista. I miss it every single day.
Searching for technical (unix, programming, etc.) content is so much easier when you can use nested parens and proper boolean language.
This is in contrast to google where searches return things that don't even contain your keywords.
This is in contrast to google where the modifiers like allinsite: and '+' and "quotes" are not respected or change their behavior over time.
Man I miss altavista...