Oh wow, looking for experts, power line/network issues

Here is the situation, I have 6 machines in the house, a 360, 2 netgear gigabit switches, a D-Link 802n router, a DD-WRTed 802n Linksys router and a set of Belkin HD gigabit powerline ports (claim they can do gigabit over the home's power system.

Now here is how I currently have it setup:

My office is where my DSL connection comes in, from there it goes to my D-link wireless N router which does the DHCP for almost all the network. Plugged into the router is one of the 2 gigabit switches that has my media server and my main gaming rig that sit on my desk hooked up. The switch then has a cable from there to the Belkin powerline plug.

My living room TV area has my 360 and a small windows machine hooked to the TV. Both of those are plugged into the Linksys router that is set into repeater mode so that it can keep a pretty solid connection back to my main network. (Keep in mind all of this is maybe 12-15 feet away from my office setup, just a couple of walls in the way.)

In the bedroom I just have a single machine hooked up to the TV, more for media than anything else since the TV is SD and only 27". I don't have this one in place yet but I plan on just tossing in a trend duel antenna N wifi card and then hooking that to a 7dB omni directional I bought. Again this setup is maybe 15 feet from the living room router and 30 feet from the office but I could never get either a G or N signal to the back room without boosting it.

The final work area is out in my shed. I was staying connected to the house by actually chaining routers together and getting a low connection in the best of weather and nothing in even "ok" weather. I sprung for the Belkin powerline adapter because it was not much more and the idea of a 10/100 network out there was a wet dream, 10/100/1000 sounded like heaven. In the shed how I have a main gaming rig and an older 10/100 laptop I have set to the side for either video or CCTV. Of course both of these are plugged into a switch that plugs into the Belkin.

The problem:

My biggest problem is laggy video. I am finding that with nothing else going on my network (even killed all web traffic) I get laggy video on both my gigabit system, the 10/100 laptop and my living room TV when I access files from my media server. The server is running Windows Home Server and I still need to set it up with each computer. To access the video files I just have them shared and the shared drives mapped, my wife finds a video and opens it in the living room with Media Player Classic. Of course if I try and access another video in my shed (have not tried it in the bedroom yet) it lags like crazy and ends up making both videos unwatchable. All systems other than the server are XP, mostly pro.

Are there any free tools I could use to monitor how much bandwidth I am getting inside my network? I really think the weak link is the belkin but I have it plugged straight into the wall on both ends just like they say. Any thoughts would be helpful and thanks for reading the novel.

Now that you know how I have