I have found Google to provide more distinct results, but Yahoo is not far behind at all
I'll say Google returns better search result. Yahoo is also a great search engine, but I seldom use yahoo to search net.
For searching Google is better. The results are related to your country and for your interests. Yahoo is used for YM mostly, and there are a lot of groups.
Google, because the results are from your country and interests like mentioned above me. It's also much smoother and easier to see the results, Yahoo is like one page full of crap and Google is just a simple white page with the thing we're looking for -- a search box
As we know that Google is no. 1 due to its database and it give good and relevant search results for any keyword but Yahoo is also good when you check backlink for your website.