Virtual PC 2007
It seems that 3D acceleration is not supported by Virtual PC 2007 but I just found a blog's article where the author found a solution to enable 3D acceleration on Windows 7 client. The trick should work only with both host and client running Windows 7.
Here is the link. Hope it helps.
VirtualBox
VirtualBox, since version 3.0, provide support for 3D acceleration with DirectX 8/9.
Unfortunately it is not very stable and in addition Visual Studio crashes when developing WPF applications and 3D acceleration is enabled.
A ticket has been opened and it says that they are working on a fix
VMware Workstation
Also VMware Workstation provided experimental DirectX support since release 5.5. But reading through their forum topics it seems that WPF development works with 3D acceleration enabled only with VMare Workstation 7 and later.
I didn't try myself but it seems promising. On the product page you can see Aero 3D working on Windows 7 and a screen shows also Half-Life!
From this page:
VMware Workstation was the first to
support 3D graphics in virtualized
environments and is now the first to
support Windows Aero in Windows Vista
and Windows 7 virtual machines. Run
even more 3D applications with support
for DirectX 9.0c Shader Model 3 and
OpenGL 2.13D graphics in Windows
virtual machines.
Evaluate the trial and let us know...