Freelanders are good cars and (if you find a reliable one) easy to live with. Whatever you do, don't risk a petrol one. As said on here already, the 1.8 and 2.5 both have serious issues. If you go for a diesel, the TD4 is the better engine and has the bonus of being chain driven. It also goes well and is economical - This is the reason I didn't buy a Disco - 25MPG vs 40MPG.
You want to be looking at a 2002 or later as by then most (emphasise the word most - and not all!) issues have been resolved. Certainly, you will be far better off from an engine and most big mechanical bits point of view.
Have a scan through this forum to see common things that can go wrong and get out there and look at and test drive all the Freelanders, X-Trails, RAV4s, etc, etc that you can before you buy anything!!
PS: Unless you fit rubbing strips to your FL (should you buy one) don't park next to dozy old fookers in Hyundai Atoz's unless you want a chunk taken out of your door!
Cheers
Rog