The best is to be able to obtain the SpectraView II kit with colorimeter and SpectraView II software. This will internally calibrate the monitor's color look up tables. If you are in North America, the combo can be ordered under the SVII-KIT part number.
Otherwise, the colorimeter included with this package is the X-Rite DTP-94. The Eye One Display II has this as far as I know, and it is considered a good colorimeter for this fine monitor.
Unfortunately, they don't sell the SV II kit with colorimeter and the software here. So I pretty much have to get everything overseas. Unless its the i1 Display 2 (is it the same as the Eye One Display II?), then its available locally - I still have to get the software from overseas though.
I have a few questions for those who own the 2490WUXi. It seems that the black now seems REALLY black and in pictures where certain areas which are dark (but not black) seem to lack colour. How do I fix this?
Also, I just plugged and played my monitor. How do I fully utilize its "potential"? Is a colorimeter essential in this aspect?