Any 6 inch used Kurt or Glacern is hard to beat if in reasonable shape. If buying new I would see which of those two brands I could get the best price on. For the home shop most any of the import parallels will work as will making up some of your own out of cold rolled steel or buy Starrett tool steel flat stock from Enco when they have a 20% off and free shipping deal. You can then make up any size you need. Yes they aren't hardened and ground but they will also not damage your cutters if you should make a mistake and run into one of them while milling. Buy aluminum and steel jaws for your mill vise from Monster Jaws. You can't buy the material for what they sell them for. You can then mill steps along the top edge of the jaws and clamp some parts without parallels. Often times it can be a waste to purchase entire sets of collets for a mill. Typically you only need about half of the sizes that come in the sets. Look at the sizes end mills typically come in that you will be using. I have drill chucks and boring heads with R8 shanks and often I end up using others with straight 1/2" and 3/4" shanks with collets because they use up much less daylight between the spindle and the workpiece. I have Lyndex and they are o.k. Hardinge is the gold standard and their price reflects it but they are the best. As said above Jacobs Super chucks and Albrechts are tops as long as the Jacobs is a older one. You pay your money and take your chances on any new Jacobs stuff including repair parts as they have offshored their products and they are not the same. I have also had good luck with Rohm and Glacern chucks. I have a 12" PhaseII rotary table and I have no complaints. It certainly is no Troyke...they are the best. Again, for the home shop the middle of the road tables like the PhaseII will do a fine job. I personally would keep a eye out on craigslist for a used table. 8" is about the biggest you want to lift with a 3 or 4 jaw chuck installed. I built a jib crane to lift my 12" table. My best advice, spend your money on endmills,a good vise, a flycutter, a boring head and then buy the other stuff as good deals surface and experience and jobs dictate.
Darrell