hmm...urs is AP set right? try checking ur production week (on the sticker on ur phone under the battery.)
if its 08w50 or before that, then ur earpiece problem quite common. send to warranty ba... lol
if not, try updating ur firmware thru SEUS. might help.

Added you into list, in addition to what ian has said, you should have tested it out first when you buy.

A note to what buyers should test on when buying a new phone:

Keypad
Joystick
Make a call, check for calling tone, the voice+volume of calls, loudspeaker, the inbuilt mic
Browse through the menu to see if there are any sudden lags

As for camera, alot of people don't know this:

You should flip open the lens cover, use your hand to cover the lens, so that the screen is completely black(blank) covered by your hand. This is to check if there are any dead pixels. By looking at a bright screen, its IMPOSSIBLE you can look for dead pixels. Therefore, that's the best way to check for dead pixels

The new firmware has smile shutter ?

A few owners here have keypad problems like yours. I just recently got mine fixed in SE center. Lucky I bought original as they told me need to change 2 keypads underneath and it will cost 200+ for just changing the keypads. Not sure AP got cover this or not.