How much is it going to cost you for the neccessary equipment? What equipment will you need? (I assume you need a NIC and something like an access point (or another NIC and a computer connected to it running ICS)...
The alternative to this would be (1) the option similar to this but runs over home phone line (think 3com makes this)... (2) wireless 802.11b... and (3) hardwiring.
Hardwiring is usually the least expensive and fastest option(as well as the most reliable)... its only negative is that it can be hard to install and often involves the most physical work to install when you have to do several rooms in a house. The times when hardwiring are perfect is when you ahve two computers in close proximity and wiring can simply be laid behind the computers... or when routing is as simple as going through a single floor/wall/ceiling.
The other 3 are all very similar... the advantage to 802.11b is that it offers proven reliability and security while being capable of the highest speed (11Mbs). You also have the benefits of being wireless. Its cons are that it is often expensive, requires some knowledge to setup correctly, and may involve some troubleshooting to get things working reliably.
The last two (network over power outlets or home phone lines) have the slowest speeds available. They are probably the least tested, and probably have the worst security available. The reliability of them is probably determined to a large extent by the environment in which you run them and the quality of the hardware you purchase.
If you are connecting one or two computers this will probably be cheaper than wireless. This is the selling point, a cheap alternative to ethernet or wireless for people who simply need a connection and who have moderate needs. This is a good option for people who do not have the knowledge or skills to setup wireless or a wired network.
Personally, I would go for a wired network if possible. But this is because I do file sharing between computers often and I also want an extremely reliable network, so I have not even considered anything else. I also have the skills to crimp cables, patch dry wall, etc... so installation will pretty much just involve a decent chunk of time to get everything done.