I have run into a problem with mybitcoin.com not functioning properly. I lost a small amount of bitcoins because of a transfer from slush's pool. It has gone through, been deducted from the confirmed amount, but has not shown up on mybitcoin.com after 10 hours. Three other transactions have gone through without any problems. Block explorer has the transaction in a block, with the correct amount of BTC being transferred to my receiving account, but it has not showed up in mybitcoin.com

Does anybody know of an online wallet that does not have problems? It seems that other people have had similar problems like this. If there isn't a good online wallet, does anybody know of a good way to store your wallet in a way that you could access it from any computer? Would storing a bitcoin program in a dropbox account be a good way, or would that introduce more problems than it is worth?