1) do they give you any discounts on park passes or dinnig?
Currently, yes, but these are not guaranteed with your contract. As a DVC member you get a $100 off your annual pass. There are no specific discounts on dining, but you can choose to purchase the dining plan (all three as of 2009) without having to purchase any passes (no package required, just a stay in a DVC).
2)i heard the yearly dues are around 600-700 and go up every year(so wouldnt that almost cover your resort anyway) i know not the poly but to stay at the poly you would use aboat load of points
Dues are based per point. Currently in 2008, Animal Kingdom Villas are $4.71 a point. For an example, we purchased 205 points, it would be $965.55 for the yearly dues. This number of points will allow for a one bedroom for a week in January, September and the first half of December or two weeks in a Studio (both sleep 4 - 5).
As for cost, you have to compare Apples to Apples, comparing a DVC to a moderate or a value resort is not a correct comparison. Comparing it to a Deluxe is the correct way.
You can choose to use your points to stay at the Poly (or any of the other non-dvc deluxe resorts), but it would not be the best use of your points. You are much better off to stick with DVC based resorts.
3)can you use this "deed" as a write off
Yes and no. You can write off the interest on your "mortgage" if you finance through Disney (and there may be some others as well) and you can also write off the property tax piece of your dues (the amount of your dues payable for property tax is spelled out in the annual report).
Nothing else is tax deductable (ie. donating a week to a charity, etc.)
4) what the best deal to buy into now,were more of the tropical theme(seeing were from chicago)
There are many resorts to choose from, but there are none that are like Polynesian, sorry to say. Animal Kingdom offers the savannah, Bay Lake Tower offers the contemporary feel, Wilderness Lodge offers a outdoor/camping feel, etc, etc, etc.
There are some other things to consider, pro and con to a DVC. First is you do not get daily housekeeping (unless you pay extra or stay concierge, where applicable). You do not pay sales tax on your resort stay. You may need to plan further out to get premium views or specific DVC resorts - like Beach Club Villas due to the limited capacity.
In the end you are purchasing an interest in a resort, and by doing so, you are bearing the risk of future performance. Inflation is a fact of life, and your dues tend to follow this rate, but so do room rates at resorts, so both will go up, but in the end you are betting (realistically in your favor) that your DVC will pay for itself if you use it and work out to be much cheaper then if you had paid cash every year for your room.
Disney has done a great job in marketing their timeshares and the rate of depreciation is very low compared to some other timeshares in the market.