The answer to your next question is no. A wireless adapter is usually much slower than fast ethernet. Typically, wireless adapters can only transfer at a max of 11 MB per second, where as fast ethernet has the ability to transfer up to 100 MB per second.
If you are in need of maximum performance, then I'd suggest dealing with the cables. If you hate cables lying around, you should look into purchasing Gecko Tape (it's amazing for tying up cables and such).
If you are looking for convenience of mobility or have the PC located quite a distance from the router/modem, then go for a wireless connection.