How does Bitcoin ever expect to be useful in the mainstream if every time people with slow internet open their wallet, it takes hours and hours to update.
If you are using v0.8, the initial download is about a day or less -- and much less if you have decent hardware and bandwidth.
If you are using v0.7, stop (or stop, if you don't have decent hardware, bandwidth and patience.)
If you are using really old hardware, consider MultiBit, which is an SPV client -- it only downloads block headers and unspent transactions for addresses in the wallet.