I did a similar switch: i have only a new iPad with 64GB/WiFi. No 3G. Because i dont want for each device a new contract.
But to be honest: I'm cheating here a bit as i have a mobile 4G-Wifi router which connect up to 10 devices with Internet. This way I can use one contract for my iPads, MBA, iPod touch and for my iPhone. Even for the iPhone it helps while commuting the 3G quality get down (too many smartphones in Tokyo).
In home and office of course I have static WiFi; no 3G required.
If you dont really often use 3G maybe you can get a prepaid contract. Plus "downgrade" the storage to 32GB I would check carefully as this might limits you (depens on what you use the device for)