I would go with PCI, unless your just not comfortable with opening your computer to install it. I've kinda learned that USB doesn't have the coverage that a PCI card has...since most USB adapters don't have the kind of antennas that PCI cards do. I wouldn't try electrical networking yet, its fairly new and I haven't heard good things about it. I'd wait to do electrical networking once they have worked out some of the problems.

I'd recommend D-Link, just because I've tried both Netgear and Linksys, and I haven't had the consistency or reliability that D-Link has given me, but that is just in my experience. But now that I think about it... you might want to get Linksys adapters for your computers since your using a Linksys router. Sometimes mixing brands is not always the best thing to do.

Borgslayer