LAN will always be the best option. If you get a newer model router, it will have Gigabit ports. Make sure you buy Cat6 cable and your internal network will be running at 1Gbps , or 1000 Mbps.
If you use an older router and Cat5 cable, you will still be at 100 Mbps.
Wireless Routers never get as high as they advertise, for example, a "G" Router can reportedly get up to 54 Mbps, but mine have always topped around 40-ish, plus, the farther you are away from the router, and interference from other networks, other signals (phones), solid walls, etc, can greatly effect your performance. N routers are just a combination of the "B" and "G" technologies, and can reportedly get up to 90Mbps, although mine never hit that mark (even with some tweaking).
HomePlugs are handy when you cant run a Cat6 cable (cement walls), and your wireless signal is hard to reach (cement walls). I used a set once, in an airport hanger. They're acceptable, but Cat6 on Gigabit ports will be your best bet.
Bottom Line, Buy a Gigabit port, wireless "N" router (100 bucks). Run Cat6 where you can. You can also run wireless off the same router (make sure you secure your network with a wpa password). You can use the wireless for convenience, but your LAN lines when you need performance.
PS -- sometimes power outages will reset your wireless network. It makes your life a whole lot easier if you have LAN lines as well.