Originally Posted by shaundalglish
There are resistive screens that support both nails and multitouch.
They are not supported by Microsoft however. But we might see them in other (e.g. Android) phones in the future.
I don't expect any Android phones with resistive screens from any of the bigger Android supporters in the industry, like HTC for example. HTC has said that they learned from the HTC Tattoo to never do an Android phone with a resistive touchscreen again. It's simply too much of an inferior experience and that makes the higher cost of a capacitive touchscreen worth it.
The problem with a resistive touchscreen is that it reacts to pressure and not to contact. That's precisely what you need if you want to operate the touchscreen with your nails, but it just doesn't work well for all other touchscreen user interface manipulations. It's just a much more pleasant experience if the screen reacts to your input without having to barely do anything, it makes using the touchscreen a much more delightful experience.
Another problem with a resistive touchscreen is the fact that because it reacts to pressure, the screen need to be flexible. This means that you can't use a tempered glass screen or something similar on a resistive touchscreen device and you can't (or it's very very hard to) make a device with a touchscreen that's flush with its bezel. The former means that your screen a more prone to scratching and also that it makes the underlying screen a bit more vulnerable to damage.
Now I agree that a capacitive touchscreen also has its drawbacks, but for a mobile phone or a PMP a capacitive touchscreen and a finger friendly user interface is preferable in my opinion compared to a resistive touchscreen. There are other market segments and usage scenarios where a device with a resistive touchscreen is preferable to a capacitive touchscreen, for example in Postal Services where the mail man can collect a signature from you on his portable device that features a resistive touchscreen or in restaurants. But for a mobile phone I'd prefer a capacitive touchscreen simply because it's much easier to use and I don't need a stylus (too cumbersome) on a mobile phone.