I'm curious what other people are doing when it comes to monitoring RAM usage. For the short time I used the built in basic alert to watch it like a volume it seemed fairly obvious it would be tough to use any sort of "blanket thresholds" when you start talking about a fairly diverse environment, particularly when you throw Exchange, SQL, 2008, and 2008 R2 into the mix (all of which will essentially chew up all the RAM it can get their hands on, and manage it fairly well when it comes to giving it up for other processes).
So how are you guys doing it, if at all? Are you really setting things up separately for each server? Did you decide it was pointless to watch available memory and instead focus more on performance counters? I'm trying to decide exactly what direction we're going here, as setting things up per-box would be time consuming and hard to document/explain for several hundred servers.