In recent weeks, I have repeatedly been tempted by various smartphones. I have not bought one yet, since I am sort of picky.
The most important feature for me is undoubtedly Linux compatibility. There is no point in buying an expensive phone if it will not synchronize with my laptop (since my primary intention would be for the phone to partially replace my laptop). I do not expect the manufacturer or my carrier to provide sync software that will run on Linux, but I do not think that it is too much to ask that the phone uses open standards when interfacing with other devices.
Unfortunately, the specification sheets for all smartphones I have seen only mention their compatibility with Windows and Microsoft Office (as is probably fitting, since their target audience is the mobile corporate type who travels a lot, as opposed to me, who grimaces each time he has to use Office for work purposes). None talk about their amazing cross-platform synchronization capabilities, or about how they can edit OpenOffice documents. This is at least partially because a large number of smartphones run Windows Mobile. It is possible that such a smartphone would work well with my computer. It is more likely that trying to configure the two devices to work well together would be extremely painful.
This is part of the reason I am excited about First International Computing's Neo1973. Based on the new OpenMoKo framework, the phone consists of all open-source software with access to a special mobile software repository. True to FLOSS ideals, the phone will also be a development platform, allowing programmers to create their own mobile applications. But unlike other Linux mobile devices like the Nokia 770 and the Sony Mylo, which both are in the same price range (about $300), it actually is a phone.
The phones will be available to the public in January, but I almost certainly will not be purchasing one of them because they have neither WiFi nor Bluetooth connectivity. They also look sort of funny, but I do not think this is a problem as long as they pass the Just Works test.
Moss-Pultz notes that the FIC-GTA001, or Neo1973, is merely the first model in a planned family of open Linux phones from FIC. He expects a follow-up model to offer both WiFi and Bluetooth. "By the time one ships, the next one is half done," he says.
 This is mostly because each time I have to go through the mental calculus of whether I can get away with using OpenOffice, or whether doing so might introduce some document incompatibilities or misformatting. Since I do not have enough time to check each document in Microsoft Office after I make my changes in OpenOffice to make sure everything looks and works alright before I send/upload it, I end up just using Microsoft Office. This makes me feel guilty, even though it almost certainly should not.