In light of events over at AGS, it's only too apparent that backing up is a good idea.
Nothing has missed a beat on this server, but it's really not any more immune to this sort of problem - same OS, same everything pretty much, coz I'm running them both.
As such, I'm currently running a recursive zip of the entire server, everything. Following this I'll run a backup of the databases and store them both on a HDD and optical media.. a snapshot of the web server.
Once this is all complete, I'll start on the MTA server, though we have a recent backup of that, it's always a nice idea to have fresh ones to capture all the stats.
Response of the resource server for MTA and the forums may be degraded for the next 12 hours as this progresses, but it shouldn't take anything out - let me know if you spot any problems... I'm on MSN.
More info as I progress.