If you are interested in the network, then you will need a full client (bitcoin-qt) and port 8333 TCP forwarded/uPNP'd to the outside world, without this you are not helping the network. To further benefit the network mine on a p2pool if you have enough hash rate, eg eligius or p2pool.in by forrestv.

This topic explains the Hashers vs Miners problem. Hashers are not miners, and Bitcoin network doesn't need them.