$1 CPM is what pretty much everyone can get, $3CPM and beyond are possible but generally reserved for people that are members of well managed Youtube networks. Gangnam style is probably a unique case in that it's a single video that advertisers will want to associate with, so I wouldn't be surprised if it's making $5 CPM ($5k/1m views) -- $5CPM average, probably peaking at 10 - 15.
If I am not mistaken the 'M' in CPM stands for 1000 not 1m. the M is a roman numeral for 1000. That would also be more on par with what I am seeing other youtubers get (see AdamGibbins's link).
I meant $1 per 1,000 views. My calculation of $5,000 for 1,000,000 views was meant as an extension of the calculations for those that wanted to work out the total.
