What do you mean exactly for storage? If you just need to make a backup, the only file you need to store is the wallet.dat, it contains your private keys, that is the only thing that allows you to access your coins. In fact, coins are not stored in your pc, coins are stored in the blockchain.
If you are looking for a client to send/received bitcoins without downloading the whole blockchain, there are some programs that allow to do that. The most famous are:
- Electrum:
https://electrum.org/- MultiBit:
https://multibit.org/They have been around for a while, and I've been told they work perfectly, but I have never used them, so I can't provide any feedback. I'm interested indeed to know if somebody here is using them...