Personly I think the 4th gen (06-present) are the best. Not really sure about the 4wd models. I have a 06 Silver SR5 with the 1GRFE V-6. It's 2wd and can off-road and mud with the best of the jeeps. I haven't gotten stuck yet. My friends 2001 Limited 4Runner 3.4L is two wheel drive too, but he has alot less power. Now if it were like rock climbing I think the 2 gen would be best due to the fact its light, has decent power and parts are cheap. I know a guy in my town that bought a 1st gen that was at a pick-and-pull for $400 and dropped a 2004 4.7L V-8 for like $900 then added a 5 inch lift. He takes it mudding and its his daily driver.