pretty much required for 'normal' internet browsing now
Depends on one's definition of normal, of course
At home I run an old clunker (W95 IE4 28k and I'm too embarrassed to say the Mhz), so I have all the 'bells and whistles' options turned off. I even set it to prompt for JavaScript. Now I don't go to game or music sites, but I find very few others where the lack of Flash or similar cr@p is a hindrance. The good ones have 'skip intro' link anyway, although they do try to make that as small as possible.
I have a power machine on a T3 at work, but I've never noticed Flash on PPruNe (not that I ever access it at work of course !).