fatshark is indeed the most popular for the phantom id say.
I personally have the Fatshark Attitude SD (kit comes with goggles, transmitter, and receiver) and a GoPro Hero 3 Black Edition.
Keep in mind if you buy a fatshark it does NOT come with a battery for the goggles (sold separetly).
I found that out the hard way =). The bad part was when I went to buy one of their batteries...I found out everywhere was out of stock on them. I ended up making my own cable that used one of my Phantom batteries. Worked out well, but eventually purchased the fatshark battery in the end.
If you go this route, you will also need to either make your own cable to connect the transmitter to your go pro, or purchase one from somewhere. I bought one online for less then $10. You can often times find all those additional items at the same place you buy a fatshark...so look to bundle it all together to save on shipping.
oh, one last thing...if you do get a fatshark system and purchase a fatshark battery...make sure you have something to charge it. It does not come with a charger. However, you can easily find adapters to use with your lipo battery charger (barrel plug to XT60).
and defintely go with the 5.8GHz as dkr said.