My iPhone has the scanlines over the screen too. Sometimes it's bad and very noticeable, sometimes it's not as bad and more subtle. I've learnt to live with it (rather than have it sent off to be repaired or replaced which Vodafone says takes "4-6 weeks") and don't notice it as much any more, but it's there.
My best friend bought an iPhone. After using it for an hour or two, realized the accelerometer was completely screwed, even after doing a software restore. Took it back to the Optus store, was told it would have to be sent off to be repaired. So basically he bought this phone and had to send it away the day he bought it. As much as he insisted on getting a replacement or refund, he was told by the store manager that their hands were tied and all they could do was send it to Apple. He received it back from Apple the following week, and Apple had determined there was nothing wrong with it. However the problem was STILL there. Safari/iPod/games which use the accelerometer automatically switch to landscape mode regardless of how it's held.
My other friend bought a white iPhone. The silent ringer switch was not straight, it was diagonal and couldn't be clicked back in place. She was told this was due to "accidental damage", therefore they could not repair or replace it, even though it was like that when it was taken out of the box brand new.
The other two people I know who have iPhones are constantly experiencing freezing and crashes (even after updating to 2.1 software) and disappointed every time they go to do something with their phones which they then discover they can't do (bluetooth file transfer, MMS, video recording, etc). Obviously that last bit isn't a fault, it's something they should've been aware of before they bought the phone, but the lack of basic phone features plus off-the-chart faulty units and problems has given this phone a terrible reputation with a lot of people. (Almost Windows Vista-like reputation.) It's considered a huge joke by so many people, which is such a shame because of all the great stuff it CAN do, and its potential. (Apple aren't helping it reach its potential by crippling the capabilities third party apps can add, limiting the apps developers can make to things like tip calculators and games.

)
I love my iPhone, was waiting over a year to get mine, and whilst I still love it and it's still the best phone I've ever owned... it's just a lil disappointing when I look at my friends who hate their iPhones, and how much better it all could've been.