They are missing from everything, people and phone dialler. I've just had another Google, and someone's Desire had set the account on the phone as @googlemail, whereby the actual address was @gmail. This rings a bell (pun) as when I set up the gmail account initially, it was @googlemail, but we then changed to @gmail because it's a neater address. I was very new to this at the time, so I think the phone is still set as @googlemail. I'll have a look when I get home...
Google still has the problem where, if you change the address from googlemail to gmail (or vice versa) then you need to factory reset the phone and set it up with the new address.... PITA

If you switch it back to the address you used during inital phone setup then it will solve the problem.... (or reset phone as mentioned above)