It sounds like you should look into either MultiBit or Electrum.
Electrum has the added benefit of using deterministic addresses. This means you only need to create a single backup of the "seed" one time, and your entire wallet can be restored at any time in the future from that "seed". Electrum has the drawback of relying on a server for communicating with the bitcoin network, and carries a small risk of a malicious server interfering with the transactions/blocks that your wallet hears about. There are various techniques used by Electrum to minimize the risk so it isn't very significant.
MultiBit connects directly to the bitcoin network, using SPV to verify payments instead of storing the complete blockchain. It still needs to receive blocks and transactions from peers to perform SPV, but it doesn't need to store as much locally. MultiBit does not use deterministic addresses, so you need to remember to create a new backup when you create new addresses.
I'm not sure which of the two wallets uses less communication bandwidth. If I were to guess, I'd guess Electrum, but you might want to ask a bit more about the bandwidth usage of each wallet in their respective sub-forums:
Electrum
https://bitcointalk.org/index.php?board=98.0MultiBit
https://bitcointalk.org/index.php?board=99.0