Addemdun: Of course there's several ways to what stats can be used. Do you want to see your own development in terms of popularity? Do you want to notice a trend? Do you want to know how popular someone is? Do you want to know how active someone is?
For any of these cases several of all the stats provided can give you an answer. Or at least an indicator. (Yeah, that's probably a better word.) But it's not always the same ones.
Anyway, my point from above is still valid: it's the combination of stats that is important, and the more stats there are the better. (Sidenote: That's why I think it's important to keep overall Pageview stats, and as prominently as they currently are. Regardless of how much hated they sometimes are.)
Any one of these but the Pageview count are pretty hard to keep track of. Except Comments – but you're pretty much responsible for those yourself (and not others). Even with helpful scripts like Deviant Statistics, it's your Pageview count that's the most easiest to follow, especially with all the graphs dA provides. But is it my favourite? Hard to say; it's definitely a combination of all the stats. And that applies to both myself and other people I visit.