I'm on my 2nd X10i now, the problem is in the usb plug on the phone, theres a usb charge wire and a data wire, my first phone stopped charging first then then stopped connecting to the computer.
I got it replaced with a re-con in repair with vodafone.
My 2nd one has just stopped charging again, you have to get it in just the right position for it to charge, but you have to keep an eye on it as sometimes it does the opposite and discharges instead! Stupid phone!
I'm now waiting for my returns envelope and hope this will be the last time I have to repair this beast before my upgrade is due.....on top of this the battery power lasts less than a day, if I go out, check in somewhere, send a few texts, it lasts a few hours at best! And yes I have even got 2 batteries so I can change it halfway through the day when it runs out! I'm never getting a Sony again until I know they sorted the battery power out