iCloud takes care of some of that, but you can't expect to sync up to 64 GB of data daily via random Wi-Fi networks (let alone 3G...).
You can sync that amount of data perfectly via wifi as long as it is 802.11n and/or if you have patience. Daily or weekly syncing it via this way does not mean it will sync all of the data. Syncing will only sync the changes and those are mostly quite small. That's why Apple offers the iCloud backup service.
However, there is a very cool feature with syncing regarding iOS5 and iTunes 10.5. It is very smart and I wish they did the same thing for networking. What you can do is sync wirelessly and if it takes too long hook it up via usb. It then seamlessly (!!!!!) switches from wireless to wired speeding up the sync! The other way around happens too. Unhook it and it will switch to wireless sync. Very awesome feature. The syncing also happens in the background meaning you don't have to think about it. If only they would do that with wireless and wired networking (hook up the cable and it seamlessly switches from wireless to wired giving you more speed and vice versa if you want/have to move). Ubuntu has the ability to do so.
Btw, if you want to wifi-sync
automatically there are 3 things you have to do:
1. iOS device and Mac have to be on the same network (mind you, not wifi, the Mac can be on the wired segment of the network like mine is!)
2. iTunes has to be running on the Mac (which means the Mac can not be shutdown or in sleep mode).
3. the iOS device has to be connected to a power source (aka charge it).
If you want to wifi-sync
manually there are two ways of doing that:
1. Hit the sync button in iTunes for that particular iOS device.
2. Tap the "sync" button in Settings > General > Wifi-sync on the iOS device.
Obviously you have to enable wifi syncing in iTunes for the iOS device first before you can even attempt the wireless sync...
Too bad that the iPhone is able to sync like this since 12-10-2011. My Treo 650 could do this via bluetooth in 2004! The fact that you can switch between wired and wireless whilst syncing makes up for that fact though.
If you want to restore the device or update its software listen to what iTunes tells you and use the usb cable to do so. Wired is still the most reliable connection thus eliminating nasty things like a connection that drops right in the middle of the firmware flashing process leaving you with a bricked iPhone. Alternatively you can use the over-the-air update stuff too, that's what it is supposed to do.