I had a 90 TD5 station wagon, and loved it. Every one's said what needs to be said about owning a defender – you either want one or you dont!
But, I found the 90 a bit too small, so chopped it in for a 110 Puma Utility. The extra space is great – can take four bikes and four people, two bikes and two people with loads of spare room, and any variation in between. The hardtop rear portion gives you a brilliant room for changing and sheltering, and a sleeping space if needed.
Parking is a bit of an art, and the turning circle is more like a planetary orbit, but the drive is so much fun overall that it's worth the cost and hassle.
If it's an option, I'd go for a 110 over a 90, but you wont regret a 90 either. Do it! Join the fold, and dont forget to wave and be waved at!