Pixie...
You have the same dilema most of us had in the beginning. I would start by looking at your vacation habits in the past and try to project what they will be like in the future. How often will you go? twice a year? once every other year? How long will you stay? what size unit will you need? What time of year will you go? Do you want to stay at WDW or is hilton head or vero the place to be?
Next get out the
point charts and figure out how many points you need for each complex scenario. Next ... how many points can you afford? Finally, i would go for the highest number of points that you can reasonably afford that will meet your vactioning needs. There is no right or wrong answer here.
With regard to WHERE to buy. If your main goal is to be at Walt Disney World, it is IMPORTANT to buy at a WDW resort so you can take advantage of the 11 month window. This means Beach Club if you want to buy through Disney. If you decide on OKW, BWV, or VWL, you will need to buy a resale.
If you buy at Vero or Hilton Head, keep in mind that you can only arrange a WDW vacation at the 7 month window... and you may not be able to get in during busy seasons.
Finally, do not fret this too much. Most people don't buy enough points in the beginning. You get there...you LOVE the room...you want a BIGGER room...you want to go more OFTEN...you want to stay LONGER...YOU NEED AN ADD_ON!!! We added onto our original contract 3 times in our first year!!! so we didn't even know how many points to get at first. We are quite happy with what we have now.
If you go with BCV, just pay attention to sales patterns (by following these boards). Then you will know how fast it is selling and when you would need to add-on before it is sold out.
hope this helps...