Must the solution for the challenge be a VM for VMWare Workstation? If it doesn't have to be, will preference be given to VM's for Workstation as opposed to Server or Player?
The VM format for Workstation 5.x is the same as the format for VMware Server and Player, so there's no need to worry about this -- it's all the same thing.
However, you can't use VMware Player to create VMs, only to play them. And VMware Server is still in beta, so it is probably not the best choice to use for creating VMs for the contest. For those reasons my recommendation would be to use Workstation 5.5 to create your VM(s).
You may want to check out the categories as well. We have prizes for consumer appliances, developer appliances and server appliances among others. Chances are that consumers will more likely use VMware Player so if you are building an appliance entry focused on consumers, you should think about user experience when someone uses your appliance with VMware Player.
As Ben says, the virtual machines are compatible across the product line but you probably would want to make it as easy as possible for someone to use your appliance.
Hope that helps.
That helps a lot. I just didn't want to spend all this time developing a solution and it not show as well as it could because of a technicality.
When I win, I'll buy you guys lunch...