I just found this forum and wanted to take a couple of minutes to tell people about collectl, a tool I've been working on for over 5 years and has been Open Source for about 1-1/2 of them. One of my goals was to have a tool that could replaces just about everything else and I think I've come pretty close as this table shows.
But what I think makes collectl unique is consistency and flexibility. You essentially get the identical format regardless of the type of data. You can display it on the terminal, log it to a file, plot it or even send it over a socket to another tool - some have done this with ganglia. If you don't like the output format you can add your own, though I don't think anyone has done this. But rather than me rant, here's pointer to a list of what I think are collectl's top features (and yes, it even has a 'top' format).
I don't know of any tools that in addition to the standard ones like *stat or sar can provide data on Infiniband, Lustre, IPMI and slabs just to name a few.
Or just go to the home page. Be sure to let me know what you think and what's missing...
-mark