Seating Position, Height in the seat, your height, these are things you want to think about, Resale price, if at some time in the future you intend to sell or Part Ex, Colour / Road Tax ( How Much) Insurance ( How much) Petrol / Diesel, Diesel is ok but do you do the mileage to warrant a diesel? Leather seats are better for keeping the seats clean, no dog hair's getting into the cloth of the seats unless you use a cover, why go for a new car? a New car looses it's value very quick, as soon as you drive out of the garage the price has dropped, whatever car you are thinking / seen, go on the reviews sites to see the reliability of the car & what the owners think about them, for a dog person like your German Shepherds a Hatchback would in my opinion be your best option, If you go for a used car take someone with you that knows a bit regards the workings of the car, you have the money "so barter on price" the garage wants to sell as they have the cars, you can walk away if they will not drop, if you see a model you like, go on Ebay>>Auto Trader & Compare the prices. lastly, do not buy in wet weather, that hides a lot of sins in a car Eg/ Dents etc.