PRJ,
9's are really the true key number because 7's are not very common these days. Handling your choices around 9's is very important to doing well betting totals. 8 and 10 are also important, but less so due to the fact that odd numbers are much more likely to come in. Note the key isn't so much thinking about what the actual numbers are, but paying the right price for the right number working around the posted totals. As we all know you can work hard to get the best number and have it mean absolutely nothing 90% of the time, but that 5-10% of the time where the number becomes an issue it is important that you did the right things to maximize your returns.
And once again, remember that using "cents" isn't the best way to do it. To really raise your success, think in percentages. A 25 cent move around a -120 is a lot different than the same move around -180 and it purely has to do with the percentages things occur at when you deal with a moneyline. A 25 cent move -120 to -145 implies something having about 4.6% more likelihood of happening. A 25 move from -180 to -205 only implies a change of less than 3%.