I love mom's lingonberry and blueberry pies. Her blueberry pies taste so soft and there's just the right amount of bitterness in her lingonberry pies, it's perfect. Oh, and she makes great rashberry pie too, the consistency is really soft and she puts some cookie crust on it too.
I also love basically any pie with graham cracker crust or pies with curd cheese/quark, sweet condensed milk or cream filling. Key-lime pie sounds perfect but I'm not sure we have it here.