First it was virtual worlds, then virtual shopping now it's virtual workspaces! Qwaq, a company that creates 3D collaborative environments for meetings just grew their piggy bank by $7M to grow the company. Similar to Second Life it uses avatars so that each person has a virtual self - but with the focus on an actual 'workspace' there is a focus on sharing and collaborating office apps including Word, PowerPoint, Excel and others. Their initial customer list which includes BP, Intel and HP, is impressive and it validates the growing interest in virtual 3D worlds.
Virtual Worlds and 3D animations is also a growing trend in marketing. Here are a few things that I'm aware of:
3D Product Demos
Already companies like Cisco, Intel and even smaller companies like Mirapoint offer 3D product views. The virtual products are also starting to replace those that get shipped out for roadshows and tradeshows with the help of companies like Kaon Interactive which bring the interaction on a large touch screen so your products can be there without really being there.
3D Holographic Presentations
Musion Systems takes that a step further with true Star Trek 'Beam me up, Scotty' type of functionality where you can have a 3D holographic image of a person appear next to you on a live stage - even if that person is thousands of miles away!
Virtual World Events
A number of companies are hosting events on Second Life - here's a machinima video of a Second Life event I was involved with when we announced Cisco's Connected Life Contest winners.
Brookstone's 3D store is a good example of this for B2C situations. The Second Life sites like the one Microsoft has can also be considered a virtual website (or "island").