Pardon my ignorance (I'm used to the Palm OS PDA world) but does iPod Touch syncing sync everything, or just changes? If it's everything, then you are correct, WiFi could be tedious, but if it's syncing just changes, then it should be a quick process if not much has changed. Syncing Palm PDA's is a change-based process, so syncing can take from as little as a few seconds to several minutes depending on the amount of updates.
And yes, WiFi eats batteries, so that's why I REALLY wish Apple would add a WiFi "toggle" application similar to WiFiSwitch. It makes managing WiFi SO much easier.