I am an iPhone 4 user. A rather heavy user.
But I'm in the same boat you're in. I keep looking at the N8 and E7 and wondering how I'd like them. A long time ago (I kept one of them), I used to have E71-2's as everyday devices and they were great. I liked them better than the Blackberries of their day.
When I first went to the iPhone 3GS, and then the iPhone 4, I found that I had to jailbreak them to get a couple of features I used to enjoy on the Nokia: Advanced Call Management and Joikuspot. With the iPhone, you have to crack them and then buy MyWi 4.0 and either MCleaner or iBlacklist to get the same things.
But on the other hand...the Retina Display has no equal, and the App Store has no equal. If you're into jailbreaking and want to add Cydia on top of that, there's no equal. Nothing like it.
Look at the photos that have been taken with both the N8 and the iPhone 4. Although the N8 has better specifications, are the pictures and videos really any better? You can find a lot of reviews of the N8 vs iPhone 4 on Youtube from the usual, very reputable reviewers. You get the feeling after listening to these reviews and comparisons, even though some of them don't say it outright, that even after spending five minutes saying how good the N8 has turned out, they're going right back to their iPhones as their everyday devices.
And if you're accustomed to the marvellous integration of MobileMe with the iPhone 4, you're going to be disappointed in the N8. Apparently the current firmware doesn't push correctly at all, and even if your phone isn't mission critical, you get spoiled having your calendars, contacts and mail automatically and seamlessly update the way they do on the iPhone 4. Even free Exchange servers like Google's integrate well and push perfectly with the iPhone 4.
But...I have to admit...after giving you all these negatives, I'm right there with you, looking at the N8 and E7 as possible toys. It makes absolutely no sense whatsoever. I
know the iPhone 4 is better. But there's just something so very neat and perhaps rebellious about buying a Nokia. They're obviously behind the times with multi-touch (but certainly as good as the 1.2 GHz best Android device), processors, memory utilisation and many other things. But there's still something just quite neat about them.
If the N8 had already dropped to $400, I'd probably already have one. Since they've stayed up around $450 at the usual discount houses, I am waiting. But I do not know if I am waiting for the price of the N8 to drop, as much as I am waiting for the E7 to hit the States with AT&T frequencies.
Bottom line: the iPhone 4 is just better. But if you get an N8, you'll find a lot of support, understanding and sympathy!