Second Life Viewers ➩ Singularity Viewer

This viewer is one of the best options you have if your into SL combat. Singularity Viewer is still loyal to the classic user interface but yet holding all the needed tools to make your SL enjoyable roleplay wise.

"A viewer based on familiar 1.x User Interface with many Emerald-style usability enhancements and extended tools for content creators, both thanks to Ascent Viewer heritage.
For roleplaying, Singularity adds RLVa to support RLV-compatible scripted attachments.
Extensive effort is being put to further improve stability and performance by implementing own bug fixes and performance improvements, backporting Viewer 2 and Viewer 3 technology.
We firmly believe that we can maintain the viewer in the long run and keep it compatible with Second Life while taking advantage of new and upcoming advances and retaining the classic user interface."