I like Range Rovers in general and would happily run an older one, despite all the panic and hysteria you get when you mention them on forums. However, I'm not sure I'd go for a TDV8, or indeed any diesel model of that age.
The TDV8 is not anywhere near as reliable as the 4.2 supercharged V8, and unless you're doing high mileage, the fuel costs won't be enough to offset the extra bills generated by a complex, older diesel. If you are doing high mileage, a 2007 Range Rover probably isn't the right car for you anyway.
One of the big bills on these used to be the air suspension, but aftermarket shocks and compressors are easy to find nowadays and relatively cheap. As I said, the 4.2 S/C is a very solid engine (I've had 3 of them in different cars so far and would happily have another), as are the transmissions. Get a well looked after SC model, check all the electrical systems work, be prepared to research any possible issues yourself instead of sending it straight to the dealer, and you'll probably be fine. I ran a 2008 SC Range Rover Sport for a couple of years and loved it. Contrary to what everyone told me, nothing major went wrong, and I sold it for more than I paid for it, just like I did with the three Jags I had previously which everyone also said would bankrupt me.