Google, Yahoo!, MSNsearch,
These services try their best to capture the whole universe of information. With every passing moment this becomes an ever increasing challenge. They provide a great service all in all.
What I feel is missing from the search engine equation are the steps taken by a searcher before typing in a keyword(s). That is to say the human typing in the keyword(s) own education, logic, thoughts and intellect pre-typing in the key search words has an equally important part to play. No matter how high powered the technology hardware, software and brains that put the search service online. Seconds of pre-thought can cut down search time.
I often used to find myself typing a generic keyword and then if the results were too diverse I would then add another pretty generic word etc. However, what I evolved to learn was to think about how I perceived the information I was searching for would look like. For example, if I was searching for a scientific medical report, my thoughts on language would be completely different from searching for a ski resort. (I am going to come back to this point when I have figured about a clearer explanation.)
I use search engines as the starting point to find the first island of new information that will help me find the next piece of information that will further refine what I am looking for. Search to me turns into island hopping to get to where you need to be.
General search is also not just about text, image searching I found can also be a great way to find text information.