Trying to track down cause of kernel panic

Been having this issue randomly for quite a while now including after the machine went in for repair for unrelated issues (and had a huge amount of things replaced). So far I can't come up with any good replication steps, it seems to happen once a day or every other day somewhat randomly. Usually it's while I'm on the web but there is a very good chance that's just because that's happening a large amount of the time on I'm the computer. Copied the crash report below, for this crash (and most before hand) it drops down to the kernel panic information screen but it has on occasion just reset (or soft reset/logout suddenly to the login screen). I think the report itself has the system information needed near the bottom but let me know if more would be helpful.

Moved report to pastebin because kept getting invalid character errors when posting here : http://pastebin.com/kbLAu1yv