Decided to jump in finally for my first post to offer you my experience.
I bought an 04 Discovery S (no sunroofs) with 56,000 miles, one owner, with all records, for 9k out here in California. The previous owner kept it in immaculate shape and I have never had any of the dreaded rover issues (gaskets, oil pump, "three amigos" ABS, drive shaft, etc).
It now has just about 90,000 miles on it, still running strong. I liked the 04 model because it offered the center diff lock of course and I found more 04 models in the Bay Area that were lightly used than others.
Whichever year range you go for, I urge you to take it to the trails in stock form and see how capable it is right outta the box. I have done some insane Northern California trails in my Disco stock (it does have AT tires and ARB sliders) such as Snake Lake, Gold Lake, Slickrock, Deer Valley, Bear Valley, all of Hollister OHV, Mono County, and parts of the Rubicon, with minimal trouble.
However, my subscription to Overland Journal has my "to-do" list for both my Disco and Tacoma growing steadily.....beware of the Journal's power...:drool:
Thats my .02. Good luck with whatever you get and have fun!