I installed one a few years ago for the family beagle at my parents house. Beagles are one of the harder dogs to contain, since they tend to track things till they either find them or lose the scent.
I bought this one (from this company):
http://www.petstreetmall.com/Outdoor-Containment/3973/481/
The installation took about half a day - but I think we ran 1500 feet of wire at least. I borrowed an underground cable installer and mounted it on the three-point hitch of my Dad's tractor. We went around the yard once without the wire in it to break up any roots or anything we'd run into, then stuck the wire in and went around again. Once that was done, we went around a third time, driving on the "seam" to close it up. It did a great job and you couldn't even tell we did anything in most places. About 1/4 of the fence required hand digging, which is why it took so long.
The fence itself works really well. The beagle learned it very quickly and has only ever gotten out once. That was because my Dad cut the wire when digging for something else, all the dog did was come sit on the back deck and beg for food at the door

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If you buy a fence from them, don't get extra wire from them if you need it. Get it from Home Depot or Lowes, it's WAY cheaper.
Highly reccomended. The beagle LOVES being out in the yard. We usually chain him up every now and then so the collar doesn't rub his neck raw.