Recently Treyarch had a poll question up for the community asking how many hours of play it should take for players to get to the next prestige level. The poll spanned the hours of less than 12, 12, 18, 24, 40, 64, and over 64 hours, and as you can guess 24 being the medium in the number span was the number that the community chose.
About 47% of the community votes decided that players will have to clock in 4 multiplayer hours to get to the next prestige level. If there are about 10 Prestige levels in Black Ops, then that means it’s about 240 hours of gaming to reach full prestige. Hopefully to increase those hours Black Ops will bring back the option of having golden guns for the over achievers also for replayability a type of zombie mode. The golden gun and zombie mode have not yet been confirmed but it would be nice to have back.