Qrobe.it: Google And Bing In A Single Interface
Link: Qrobe - Search Engine
Having performed a search you are presented with the results with tick boxes in the top right of the page:
Google, Bing and Ask.
You can select or deselect the search engines as desired giving any combination of the three you would like.
The image search uses only Google and Bing. Bing is of limited interest to me. However what I do like about this interface is that it will add to the search results when you have reached the bottom of the page [if there are more results to add] rather than forcing you to load a second, third, fourth,... page.
I liked it.
Edit: I also liked the 'Peek' link: Click the Peek link to veiw individual results in a frame [one result at a time]