One of the main reasons that I haven't bought an iPhone, apart from the hoops that you have to jump through to get it on the 3 network, is that it didn't support the iSilo document reader. Since iSilo is one of the main document formats for mobile devices (since the days of the Palm Pilot Professional - remember that?!), that would be a bit of a major pain, especially as most of the documents I read are in that format.
Fortunately after a lot of noise has been kicked up on the iSilo forums by iPhone/iPod Touch lovers, this application is now available from Apple's App Store.
One less reason now for me to get an iPhone!
UPDATE: oops, that last line should read, "One less reason now for me to not get an iPhone!".