You have many choices available to you. You will certainly want a development SharePoint environment, and this can be installed on a Windows Server 2008 virtual machine, or directly on your Windows 7 installation along with Visual Studio. This is a little trickier to set up, and you won't have the convenience of being able to roll back your environment using snapshots. It really is a personal preference which way you want to go (I use the Windows 7 approach because I only have 4Gb of memory on my laptop). You have enough memory to make installing in a VM an option, but you still might want to have all 8 Gb available.
You might also consider installing Windows Server 2008 instead of Windows 7 if your workstation is purely for development and you have another machine available for day-to-day use.
Whichever way you go, be sure to avoid the "stand-alone" option when running SharePoint setup, even though it is "just" a development environment. Install SQL Server or SQL Server Express (with tools) separately and use the "Server Farm" install option.
Some links:
Setting up development environment on Technet
SharePoint 2010 Development
Sahil Malik's blog