Hi,
Of all times, my favorite search engine was Altavista. I don't mean it was providing better results that nowaday's search engines. I mean, the one which I enjoyed the most... I might be wrong, but to me, it was the first to have a crawler and therefor was indexing "lot" of sites, and so was not just a directory, like Yahoo was initially. I remember finding this thrilling, and discovering a lot more sites, of all size. So, over all, this is my best "souvenir" of Search engines.
:)