Windows 8 & Second Life do work. Here's proof >>
Second Life 3.3.3 (259953) Jun 18 2012 19:31:54 (Second Life Beta Viewer)
Release Notes
You are at 252,355.0, 284,951.0, 1,006.4 in Rinji located at sim6036.agni.lindenlab.com (216.82.12.90:13003)
Second Life Server 12.06.20.260188
Release Notes
CPU: Intel® Core i5 CPU M 430 @ 2.27GHz (2261.03 MHz)
Memory: 7982 MB
OS Version: Microsoft Windows 8 64-bit (Build 8250)
Graphics Card Vendor: NVIDIA Corporation
Graphics Card: GeForce GT 325M/PCIe/SSE2
Windows Graphics Driver Version: 8.15.0010.2302
OpenGL Version: 3.3.0
libcurl Version: libcurl/7.21.1 OpenSSL/0.9.8q zlib/1.2.5 c-ares/1.7.1
J2C Decoder Version: KDU v6.4.1
Audio Driver Version: FMOD version 3.750000
Qt Webkit Version: 4.7.1 (version number hard-coded)
Voice Server Version: Vivox 3.2.0002.10426
Built with MSVC version 1600
Packets Lost: 841/38,340 (2.2%)