Creating 3D text in After Effects has long been a cottage industry, generating many workarounds and 3rd party plug-ins.
Adding to the parade is one of the big new features in After Effects CS6, the extrusion and material options in the Ray-tracing renderer, which almost requires an Nvidia GPU. Many will benefit from beautiful renders with the new features, though many will get bogged down by requirements, render times, or inadequate features, and turn to older methods surveyed here.
Note: Hmm, faster seem possible for the ray-tracer! "At SIGGRAPH 2013, Pixar describes how they achieve fast interactive lighting preview using NVIDIA® OptiX™ Technology and GPUs in a Katana-based production pipeline."