i think many people are using Taiwan's market viewpoint to view this new product. however, Taiwan's market is so small comparing to other market.
Google maps is pretty good in North America and most part of Europe. If iPhone can sell well in these 2 market alone, it will be amazing volume already.
I don't know how popular the iPhone can be.. however, I do see some potential problems.
1. In the US, most people change their cell phone every year or every 2 years. because once the contract is up, people can get another new phone for free. I don't know how iPhone fit into this model.
2. No memory card slot. As a smart phone, or even cell phone, i think a memory slot is very important. 4GB is really not that much if you have to put Songs, Photos, Calenders... etc.. With external memory card slot, a person can put all his/her songs or photo into one memory card and just plug in when needed, more like PSP model.
however, i do think iPhone will sell well because the whole iPod family has become an huge market for accessories. within just few month, we will see a lot of iPhone related accessaries on the market. The few possibilities i can think of right now are:
1. Full function remote control for home theater and everything need a remote control. 2. Packet Reader. One can download a whole book in PDF and read it on the go.