Another vote for the iphone here, I used to have a blackberry, and when it came to upgrade I spent ages in the shop trying out HTC phones, motorolla dext, etc. Nothing even came close to how easy yet powerful the iphone really is
The lack of flash support is lame, but to be honest who actually wants to run flash things on their phone? If you wanna play crappy flash games, you can get the exact thing you want in the app store for free usually.
And as somebody else said, youtube has it's own app so you can still watch videos
500mb fair usage policy does sound really limited, but it takes a lot of internet use to actually get over that, I reckon the only time you're likely to do it is if you get REALLY app happy and download a ton of crap