-Flickr
You can still take/send pictures the same way, snap a picture, and email it to flickr. There’s an option for this on flickr that will give you an email address that automatically puts them on your photo pool.

-Google Maps
I find it much better on the iPhone then I did on Windows Mobile, minus one key feature… I can’t tether my bluetooth GPS device to the iPhone, and this really sucks. Oh, I think Live Maps for Windows Mobile is much better then gmaps.

-Active Sync
I miss this feature the most, however, most of the things that I’ve read concerning the iPhone state that this will probably be included eventually in a software update. I really hope so at least.

-Laptop tethering
http://cre.ations.net/blog/post/tether-your-iphone
That just came out not too long ago, haven’t tried it yet, but it sounds like it works well.

That said, I’ve had a blackberry, I find the iPhone interface 100% more usable. The lack of 3rd party apps really really ticks me off, but I haven’t missed them yet. The voicemail on demand feature is pretty cool, the screen is beautiful and responsive, web browsing is better then anything I’ve used before, and the iPod portion is perfect, all that I could have asked for. Oh, the videos looks stellar, even YouTube looks good if you’re connected to WiFi.

Worst case, it would be an expensive iPod, but I have a feeling you’ll use it as a phone too if you make the switch.

-Aaron L.