The OP didn't use the IPhone as a phone though so it wasn't for that reason he had two....
That is sort of correct but not quite - it is tending to work that way as because I work for myself my personal contract phone (n95) is being used more and more for business so is being ignored more and more. Caller groups are fine if the number is not witheld.
The iPhone I origanlly bought as an on the side project to write software for (yet to find the time) - it is however proving useful as a PDA for a number of reasons - I have my gripes but nothing I cant work around at the moment.
My comment was more that I need an iphone for my projects but am not sure whether to accept a free upgrade on the N95 to a N97 and keep with two or go for the 02 route and port my number. Either way I will end up keeping one phone with me for day to day use - I was more interested to see how the n97 compares in things like web browsing and mail use which is very good on the iphone.
Keeping the iphone and going onto contract is an option but at the minute the phone is costing me nothing (and will cost nothing till may 2010) in upkeep as all data is free for the first year and I make outgoing calls on my nokia. The contracts on the iphone are expensive and not worth migrating to as I would end up paying for the phone twice, so if I was going to go for an iphone tariff I would get a new phone and sell the old.