Besides flash, hitting javascript-infested pages with the age-old unoptimized javascript engine in microB would also seem to stress the CPU a great deal.

At least with the Flashblock addon the former can be controlled somewhat. Firefox's Noscript addon is great on my desktop but it doesn't seem that Nokia/Maemo's outside volunteer Browser-addon team is very active these days.

In related opinion I'd say that Nokia's pricing for batteries is discouragingly high and considering how people often dump their phones when the battery starts dying (encouraging throwaway culture) it is possible that the stock currently available on store shelves is already old out of the box! (ie. manufactured a long time ago).

How I wish that device makers would settle on a few standard sizes of batteries so also credible third parties could continue serving the market and even improving capacities and charging behaviour like happens in the AA/AAA NiMH world.