All very good advice - a few things I can add are.....
1) Discus do best in groups of 5 or more as they are a very social creature and enjoy the company of other Discus. That doesn't mean that you can't have two and have some good results - some have done this quite successfully. However Discus stress very easily, and they seem to be able to handle it better when they are in a group.
2) The tank should be located in an area of the house that is realatively secluded from passers by. Having it in the hallway or near an area that people walk by frequently isn't good as Discus can be easily startled, and again, may become overly stressed by this.
3) When discus get stressed, they are more subject to contrating diseases - so care must be taken to reduce stressors. Having a hospital tank standing by "just in case" is always a wise investment. This should be a bare bones (BB) tank with only a heater & sponge filter. Since hospital tanks for Discus routinely require at least a 50% water change daily, having a fully cycled tank on standby isn't really neccessary.
4) Adult Discus can be maintained with only one feeding per day, but that one feeding needs to be a protien rich one (anything other then adults do require multible feedings per day - usually 3). A feeding net or cone is a good idea to keep the detrius & left over food at a minumum when keeping adults. A good group of "grounds keepers" (corries, ect.) is a must. Also, I wouldn't feed frozen beef heart to Dicus in a heavily planted tank. This causes a huge bioload on the tank - but if you must - then be sure to vacume the gravel below the feeding cone/net immediatly after each feeding. Failure to do so can lead to some pretty nasty water conditions. You should keep in mind that most Discus prefer a varried diet, so after you determine what foods you are going to use (and the ones your Discus prefer), vary them throughout the week.
5) These fish are very easy to take care of as long as your water quality remains consistant... so regular testing of water parameters is a must. I see from your post that you KH is 0 degrees - which means the buffering capacity of the water is too low to maintain a steady pH. I would suggest you increase the KH of your water to prevent pH swings. Also, bringing the NO3 down to 10ppm would be wise too.
6) Last but not least, when you decide to purchase you Discus get them through a reputable breeder (not the LFS).
The link in GulfCoastAquarian's post is a very good forum for Discus in planted tanks - but be sure to also pruse through the remaining forum discussion areas as well. You will learn a great deal about the special needs and concerns that need to be addressed when keeping Discus in your tank. You can also learn about most of the breeders, and what they specialize in rasing/selling (pigeon bloods, snakeskins, turks, wilds, marlburos, ect.). IMO nothing looks better then wilds in a planted tank- so if this is going to be your choice, then you should contact Al (brewmaster15) on that forum in regards to getting some wilds for your tank.
Bet of luck on your quest for Discus