I am by no means an expert, but this is how we determined how many points that we would need. We knew that we wanted to stay in a 1 BR for a week at least once a year. I put the points required at each resort we were interested in staying at for a 1 BR for that one week time period into a spreadsheet for easy comparison. I used standard views if applicable to try to compare "apples to apples" as much as possible. We started at the 160 base and then went up in ~20 point increments to see what options would be available to us. We settled on 225 points.
Our Guide told us that points could be reallocated, but the amount of points in the entire system would remain the same. I would use the 2010 charts to make your determination since they will be changing next year. For us, the change is not an issue. We will be staying at SSR in a 1 BR for 4 nights (including a Friday & Saturday) for 225 points this year. The same stay will be 112 points next year, 10 points cheaper. We are staying at BLT in a LV studio for 4 nights (also including Friday & Saturday) for 76 points. It will be the same number of points next year. I can't speak about point changes in previous years, but this is definitely the place to have that question answered.
We really did not factor in any increases when we were first making our determination. We selected the amounts of points to give us the most options, so I feel like we will be alright.
I hope that this helps. I poured over this board when we were making our decisions regarding location, number of points, etc. It is an excellent resource.