If you are looking for programs to play those file, check with VLC or Media Player Classic. Both of those are usually pretty good. Also, make sure your computer is up to the task hardware wise, as you need a more powerful computer to play HD video smoothly.
As far as tape goes, the "standard" is DV. But when you go to the store, you will see DV and HDV tapes. You can actually shoot HD on the DV tapes if you want to save money. HDV is usually at a higher standard and will have less of a chance of dropouts when recording. I would just stay with DV tapes, unless you have something extremely important you are recording, such as a wedding, then you may want to go to an HDV tape.
Also, be cautious when using Sony tapes as some, if not all,  use a wet lubrication system. The other tapes, such as TDK, Maxell or Panasonic is usually dry lubrication system. The Sony tapes may cause issues when you use them, then try to go to a dry tape. I would personally not use the Sony tapes and go with a dry tape and stick with it. Choose a brand and stick with it for fewer problems.
I would recommend going with Panasonic.