LeMond bikes are quite good; their high end bikes are comparable in quality to anything out there. Whether the bike you're looking at is a great, good, or average deal depends on the particular model of LeMond frameset and Campy components. If the components are Campy Record or Chorus, then it's almost certainly a great deal. If Centaur or Veloce (or Daytona) it may be a good deal. You might want to search the particular model on ebay to see what other folks are trying to get for it. However, the most important thing is whether it fits you. It might be a great deal, but it won't really matter if it's a 59 cm frame and you should be riding a 53 cm.
If you're just thinking about a road bike to ride occasionally and don't expect to get passionate about it, then $800 at your local bike shop will get you a good, new bike that you can be certain will fit you appropriately. On the other hand, I'm a firm believer of getting the highest quality bike you can afford; you just may get the road cycling bug big time! It's a great sport and one you can enjoy for a lifetime.
A great source of info and reviews of road bikes & components can be found at:
http://www.roadbikereview.com/Good luck to you!