It seems a bit difficult to find out how many bitcoins a specific wallet contains.
How does people keep track of it? Manually??
Manually? That's more troublesome than loading the wallet in the correct client.
If you really need to find the balance (
spendable?) without syncing the client, you just have to import the master private key to a light client that supports it(
eg. Electrum).
How to get that key?
Remember your other thread about importing a wallet into another wallet?
That dumpwallet file contains the Master Private key, it was saved to the location of your bitcoin-qt.exe if you didn't specified the directory.