I'm not sure how many people who follow this have even tried collectl but I wanted to let you all know that I just released a set of utilities called strangely enough collectl-utils, which you can get at http://collectl-utils.sourceforge.net. One web-based utility called colplot gives you the ability to very easily plot data from multiple systems in a way that makes correlating them over time very easy.
Another utility called colmux lets you look at multiple systems in real time. In fact if you go the page that describes it in more detail you'll see a photo which shows the CPU loads on 192 systems one a second, one set of data/line! in fact the display so wide it takes 3 large monitors side-by-side to see it all and even though you can't actually read the displays you can easily see which systems are loaded and which aren't.
Anyhow give it a look and let me know what you think.