This is a page with links to various trails that I either like or would like to try.

NJ Trail Series By far my favorite trail running events. Race Directors are fun, caring and excellent people
NJ Trail running Good site, good links, excellent administrator
Dirt World with a link to MTB Trails in NJ Columbia Trail, etc
New Jersey Hiking trails This site contains GPS Hiking maps of Northern New Jersey
Patriots Path Not sure if this is 14 miles in total, or 14 out and back.
New York – New Jersey Trail Conference SSIA
The Raritan Valley Road Runners Delaware and Raritan Canal Path
The Mountain Madness 50K A trail run  I am doing with some friends on 10/17/09
Mountain Bike Reviews Looks to be a good source for trail running
Listing of Trails by State Cool site from ATRA (American Trail Runners Association)
Batona Trail (Back To Nature) 4th Longest Trail in NJ  according to Wiki
5th Annual BATONA TRAIL RUN SERIES SSIA A  trail blog that lists local trail runs a long trail in NJ.  Urban, etc.
Henry Hudson Trail 22 Miles starting at Lloyd and Gerard in Matawan.  I have read that this is a poor trail, with a lot of street crossings
D&R Canal Trail Shows various access points
NJ Trails Association Interesting site
Wikipedia NJ Rails Trails SSIA
Hill Runners of Huntderdon Lots of routes, etc.
TowpathGuy’s Towpath Guide Guide to the Main Canal and its towpath in the Delaware and Raritan (D&R) State Park of New Jersey.