We present a discussion and initial empirical investigation of user-interface designs for a set of three Web browsers. The target end-user population we identi"ed were experienced software engineers who maintained large Web sites or portals. The user study demonstrated the strengths and weaknesses of two conventional 2D browsers for this target user, as well as that of XML3D, a novel browser that integrates an interactive 3D hyperbolic graph view with a more traditional 2D list view of the data. A standard collapse/expand tree browser and a Web-based hierarchical categorization similar to Yahoo!, were competitively evaluated against XML3D. No reliable di!erence between the two 2D browsers was observed. However, the results showed clear di!erences between XML3D and the 2D user interfaces combined. With XML3D, participants performed search tasks within existing categories reliably faster with no decline in the quality of their responses. It was informally observed that integrating the ability to view the overall structure of the information space with the ability to easily assess local and global relationships was key to successful search performance. XML3D was the only tool of the three that e$ciently showed the overall structure within one visualization. The XML3D browser accomplished this by combining a 3D graph layout view as well as an accompanying 2D list view. Users did opt to use the 2D user-interface components of XML3D during new category search tasks, and the XML3D performance advantage was no longer obtained in those conditions. In addition, there were no reliable di!erences in overall user satisfaction across the three user-interface designs. Since we observed subjects using the XML3D features di!erently depending on the kind of search task, future studies should explore optimal ways of integrating the use of novel focus#context visualizations and 2D lists for e!ective information retrieval. The contribution of this paper is that it includes empirical data to demonstrate where novel focus#context views might bene"t experienced users over and above more conventional user-interface techniques, in addition to where design improvements are warranted.