I find that the "transaction time" shown in the client is actually the receiving time of the transaction but not the sending time.
When old wallet was opening and downloading new blocks, it shows that there is a new transaction one minute ago, but in fact it was three months ago. This behaviour is really confusing and, even more, it shows ten thousands confirmation for that one minute transaction. I can only go the blockexplorer to find the correct date and remember that this transaction was sent between my wallets. Rescan does not solve this problem. Also, it is a problem that there are no simple way to check this in the client.
I really think the blocking time or sending time should be display in the client instead.
+1, had to figure that one first time i used the 0.5 client