I've been using the Search box much more frequently since Nick deployed his Lucene magic. Beats the Google site: selector hassle and the results are generally good. One thing it doesn't do however is consider words in the code snippets. I do post a lot of code snippets and I'm having a tough time finding them back. I'm concerned that if I can't find them back then neither can anybody else that uses the SO search box.
Sample query: user:17034 filedrop
Does not find this highly upvoted answer. The user selector makes no difference btw, it puts a +15 answer on top.