For mobile banking, I am going to have to rely on my bank's website. I bank with Chase, and Chase doesn't have a Windows Phone 7 app. It's a shame, too, because the iPhone app lets me deposit checks by taking a picture with the iPhone camera, and now I am going to have to actually go to the bank to deposit money.
I also had to go through and replace some of my games from my iPhone--Tetris, Angry Birds, Need for Speed, Sonic the Hedgehog, and others. Unfortunately, Electronic Arts hasn't yet created Windows Phone 7 versions of my favorites--Madden NFL, and Tiger Woods Golf.
I am going to digress from Windows Phone 7 for a minute to get on my soap box. It would be nice if app purchases were cross platform. In other words, if I have given my money to an app developer--say Rovio for Angry Birds--and I ditch my iPhone for a Windows Phone 7 smartphone, it would be nice if there was a system in place to allow me to take the investment I already made in the app, and roll it to the new mobile platform.
I know it's a pipe dream. I know that just isn't the way things work. I mean, if I switch from Windows to Mac OS X, Microsoft isn't going to just give me a free copy of Microsoft Office for Mac OS X just because I've been a loyal Office user on Windows. I get it.
Without such a system, though, it makes it a more difficult decision to switch platforms. Many of the apps I used on my iPhone are simply not available on Windows Phone 7, or they are free apps--like the Facebook and Twitter apps. But, just for the small subset of apps that have a Windows Phone 7 equivalent and cost money, I had to spend $75 buying apps that I already own.
Of course, with Windows Phone 7 that investment is offset somewhat by integration of Microsoft Office apps that replace my investment in iOS apps like Pages, Numbers, Keynote, and Documents To Go. In the end, I was able to find direct equivalents for most of the crucial apps I rely on. With 30,000 to choose from, I am sure I can find what I need for almost every purpose.
Summing up the experience, I would say that the majority of apps that I really need, or actually use have Windows Phone 7 equivalents available--the most notable exception being the Chase Bank app. As for the rest of the apps, with 30,000 to choose from I am pretty sure it won't take me long to find apps I like and get back up to that 120 range.