Okay. For anyone worried about maxing out too quickly, which would mean that we all end up with the same character, here is something to think about.
Todd has already confirmed that the rate of levelling will be somewhere between Fallout 3 and Skyrim, and so the estimate I have been using is 25(2*n+4)(n-1), where 'n' is your current level. Also, because we know the total number of perks on the chart (275 including the 7 training perks), as well as the maximum number of stat increases (42), we can work out the highest achievable level, which is 311.
Lets look at a 'halfway point' of level 160. By this time, you would have acquired a substantial number of perks and stat increases. But there would also be a huge number of perks still to go (over 150 remaining ranks if you'd maxed out all of your stats by this time). The XP required to achieve this level would be 1,287,900. This is far more than the total XP from all previous games combined. If you averaged 2,000 XP per hour, this would take over 640 hours!
Now lets look at the maximum level of 311. To reach such a level, you would need to acquire a total of 4,851,500 XP. This is almost 4 times the amount required to achieve level 160, and would take over 2,400 hours to achieve. If you played for 4 hours a day, 7 days a week, you would not reach this point for over a year and a half.
And so, nobody is going to have to worry about losing replay value, or everyone ending up with the same character. At least not for a very very long time...