Also keep in mind that as the number of transactions go up, the transaction fee reward from solving blocks will also go up.
To take the example used in the wiki article mentioned above: say the network was handling 2,000 transactions per second. This would be costing at least some people a lot in bandwidth. However, assuming a block takes ten minutes to solve, then there would be 2000 * 60 * 10 = 1,200,000 transactions in it. If the average transaction fee is 0.01, then that would be a 12,000 BTC reward for solving the block. That's ~$70,000 at today's exchange rates.
The fee is going to drop by orders of magnitude soon imo.