IMO you should get the following DLC packs:
1. After Dark (Gives you a sanatorium to skate at night, gives you Skate.Park pieces)
2. Danny Way's Hawaiian Dream (Gives you an area with great tranny and a sick street spot. You also get pieces for parks)
3. San Van Party Pack (Gives you the Art Gallery, Res and a new place known as Maraffa Skatepark from OG. You can also get over the fence and find Mini Mega and a few classic OG spots based on street. It also gives you Park pieces)
4. Skate.Create Pack (No doubt your going to need this, it gives you awesome Park pieces so you can make Skate.parks and it allows you to play DLC parks. Even make your own!)
5. Maloof Pack (Just get it you'll need it for DLC parks cause it gives you Park pieces and if you want to skate Maloof's 2010 course.)
I don't own the Filmer Pack. But that's up to you!