PC Magazine got a "display expert" from DisplayMate Technology to evaluate the screen performance of the DS Lite and the PSP. To a casual observer, both have stunning displays. But how do they fare when they're analyzed by the same methods used on high-end HDTVs? The report is incredibly thorough, so I'll just give you some key highlights:

• Both the DS & PSP screens feature incredible DPI (dots per inch): 110 for the DS, 130 for the PSP. The PSP is the clear victor here, cramming in more pixels into its screen per square inch. (For reference, a 19" LCD monitor has a DPI of 86. So both screens are quite impressive.)
• The DS Lite's brightness is no joke: it can go as high as 200 cd/m². The PSP, even when plugged into an AC outlet, can only produce 148 cd/m². When running solely off of battery power, the brightness drops even further to a maximum of 115 cd/m². (Clearly, Nintendo wants to destroy your eyes faster than Sony.)
• Although the DS Lite is much brighter the the PSP, it has an extremely limited viewing angle. The PSP outclasses the DS in terms of viewability, earning it "first place among all of the mobile displays." (Clearly, Sony wants everyone on the subway to be able to see the smut you're watching on the go.)