I decided to run some tests on a hunch that this is a packet loss problem. I ran this test several times so I can confirm the results.
I usually run Xsyon with Firefox for the forum and Ventrillo for the guild chat running in the background. With these three running I get disconnected from 2 to 20 minutes with a ping of 32 at idle (standing still) and 45 to 185 with lag spikes while moving around. I shut down both Vent and Firefox and I ran Xsyon for an hour with no issues and a ping closer to 35 with no noticeable spikes. I logged out, started Vent and Firefox again, then ran Xsyon and was disconnected in a few minutes. I then shut down Vent and ran Firefox only and Xsyon ran fine but with a slightly higher ping of around 45.
I would be curious to see what other people are running in the background IE Vent, IRC etc. and if they can duplicate this. We have good broadband internet here and I have no problem running vent with Vanguard, AOC, WOW Etc. I watch Netflix with no problems. I believe that while Vent is running it's eating up enough bandwidth to cause some packet loss and thereby causing a time out and disconnect with Xsyon. I don't know exactly why this is happening, but for now I can run the game fine with no disconnects as long as I don't run Ventrillo. I hope this helps.