1,000 metrics per server is quite reasonable. I work for a performance management company and we handle thousands of time series metrics per monitored server at one-second resolution.
above, copperlight quotes about 3%-5% of metrics being system-level. A pretty small number would be process-level, I'm guessing, with the vast majority being app-level.
At Netflix-sized, the answer to pretty much any question is "a lot." :)
How much traffic does that add up to? It seems a lot.