I am having this same problem. I have been running the Bitcoin client for many hours now and it just seems to be eternally synchronizing, stuck at about 75% of the progress bar. I tried to send myself some bitcoins via Daily Bitcoins, but the transaction still has not appeared in the Bitcoin-Qt application's "Transactions" tab. Do I need to wait until it finishes synchronizing before making transactions? How long should synchronizing normally take? How do I make it synchronize faster?