Expansion Board

They're all pretty much dead. EISA never really caught on as it was supplanted by PCI. Same with ISA. MCA was IBM's attempt to create a proprietary interface, which pretty much failed entirely. PCMCIA is pretty much for laptops, and it is being phased out as well.

PCI is the current most common expansion bus presently, but it is being replaced by PCI-E. The only reason you would want an expansion board is when you need backplanre access speeds. The bus I would recommend is PCI-E, then Firewire, then USB. USB has latency issues that will hopefully be alleviated when USB3 rolls out.