I have a new Iphone with no data plan. It's working pretty well. I know exactly what I'm missing by not having data as My wife has an Iphone with data. I have the Data cut off at source from Rogers so I won't get burned with charges. So far I have been leaving my 3G setting "off". My questions are:
1) does the 3G network have anything special to offer for phone use if not getting Data (range reception etc.)?
2) can I even use 3G with Data shut off?
thanks.

If you enable 3G you will be on the HSDPA network rather than the GSM network - but if you aren't using data there's really nothing to gain. Call quality may be negligibly better.