People will say that slow down and other issues you've listed do not affect them; therefore you must be doing something wrong, but done so in a very passive-aggressive manner.

With that said, I've seen slow down on my N900 after my last two trips - and it's only been used through 5 recharges - it looks new, it should act new.

But it doesn't. With that said... do you have anything you've added from Extras or Devel? Have you pulled a reboot via the Terminal in a while? Have you cleared your browser's cache lately? There are quite a few other things, but I find that a simple reboot kills my slowness... for a while.