There are several ways of looking at this, so I'll run through a couple variations fast.
1. Just need to get an edge on the knife, don't want to spend much money.
2. Need at get a great edge on the knife as fast as possible and money is less important.
3. Have an interest in learning all about sharpening and different edges.
1 . If you just want a shaving sharp edge on your knife at the level of refinement that works great for a kitchen knife, the King 800/6000 combo stone will do it at about about $55.00 http://www.chefknivestogo.com/kingcombostone.html
. Sharpen on the 800 side and strop on the 6K side and you will be all set.
2. If you want something fast, the Nubatama Ume 1K speckled medium http://www.chefknivestogo.com/nubatamaume1k1.html
at $67 and a Rika 5K http://www.chefknivestogo.com/suri50grst.html
at $50 is a great combo.
3. The perfect knife edge is a very personal choice. What is perfect for me is very unlikely to be whats perfect for you. Variables like how much pressure you like to feel in the cut, how much feedback as the knife is cutting, the product being cut, the blade the edge is going on, the board you are cutting on are just a few of the considerations. Some people like the edge that comes form stropping a 1K edge on a 6K stone. Some people prefer the edge that results from sharpening on a 1K, 2K, 4k, 8K etc. There are almost endless combinations that will all, depending on your technique, result in different types of edges.
There is the sharpening experience itself. A lot of people on these forums sharpen for pleasure, myself included, which means we take the feel of the stones into account when we choose stones. For example. Some stones are hard and feel like sharpening on a piece of granite. Other stones are soft, more like sharpening on chalk. Some stones have a buttery feel. Again, endless variations.
Its a gradual learning process. A way to get started is to get a couple stones and play with them a bit. Ofter a while, you will start to notice that you might prefer a harder stone, a softer stone, something that leaves a bit more tooth in its grit range, something..... and on and on.
Anyways, you came to a great place. Lots of sharpening enthusiasts here from all walks of life with many perspectives. All happy to help.