If you have the PCI/PCIe slots for them, separate NICs will be less expensive. If you don't have the extra slots, Intel make a line of PCI/PCI-X, and PCIe dual-port and quad-port NICs: Intel PRO/1000-series. These use the em(4) and ixgb(4) drivers. Very reliable NICs. We use a variety of single-port, dual-port, and quad-port versions of these at work. Can't comment on the prices, though, I just make the recommendations, and the bosses upstairs approve the funds.