I would strongly disagree with this. I actually would prefer the device to be a separate appendage, and purchased separately from the device.

A built-in stylus has the unfortunate side effect of generally becoming a required part of of the UI and bundled applications. A stylus that is an accessory can be purchased as a specialized tool for use by those that actually want such functionality. As a part time artist, I have no qualms with packing a tiny pen in addition to my casual use tablet.

But herein lies my discontent: I hate stylii. I like active-digitizers, digital pens, etc, or more generally pens-that-omit-hand-input-and-only-register-the-tip-and-thus-not-requiring-the-user-to-hover-his-hand-over-the-display-when-writing. This calls for an active system, uniquely sensitive capacitive systems and weirdo pen dynamics, or some advanced APIs.

Only the HTC flyer thus far seems to fit the bill. Other than that a stylus isn't a major selling feature for me.