you have to qualify your question:
100 baseT ethernet (100 Megabits) is faster 802.11g wifi (54 Mbps) and 802.11b wifi (11 Mbps).
However, surfing on the internet between ethernet and wifi should be about the same. Most ISP won't provide you enough bandwidth to exceed 11 Mbps, and by no means are you going to get close to 54 Mbps.
Now, if you are going to mac to mac then yes you will see a difference in large file transfers.