Although I voted for 500, which is how many I have, I realized that your question actually asked how many is enough. To that question, I'd probably say "more". It seems to me that our DVC vacations keep growing to meet the number of available points. There are always opportunities to take a quick trip - if only we had the extra points.
Interesting ... the poll seeks a number of points per person. As most of our discussions are based on family or household vacation habits ... adjust your response appropriately based on the number of family members.
We started with 210, added 40 to get to 250, then quickly added another 50 to get to 300. Shortly thereafter we added 100 when our daughter became a DVC member herself. And then there was another 100 when she worked at the Disney Store. Between us we've now got 1,000.
I definitely see us using whatever amount we have available. We have been DVC members for about a year and a half, we started with 200 points and added another 200 this year. I just hope I'm not starting a trend of adding on every year.
Realistically I could see us having 600 or more points and using every one of them. We live about 4 hours from HH and only about 9 from WDW so long weekends are definitely doable for us. I'm also raising 2 Disney fanatics so I hope for my wallets sake that my 400pts will keep us satisfied at least a year or two