That's actually the exact kit I ordered when I finally upgraded to the 3.

That kit is a slight waste of money. I'd still repurchase it, because I knew that at the time. Honestly, I just went with what was 100% idiot-proof, because otherwise I tend to forget the little things.

• The heatsinks probably aren't necessary, but don't hurt either
• The adapter is a good-quality one. Some people recommend using a cheap phone charger; I don't think most of those are designed to provide a continuously-reliable power supply
  • Also, this one provided enough juice to hook up an external hard drive (1TB 'WD My Passport Ultra', though I imagine any slim external would work just as well)
• I'm rather fond of the case. It covers the top nicely, but if you do decide you eventually want to fiddle around with the GPIO pins, then the top lifts off (exposing the pins and other connectors, but still covers the rest of the board)
• I'm neutral on the microsd reader. Not the best I've used; not the worst. I was mostly using it to transfer files from the old pi to the new one, so I haven't really 'put it through its paces'
• I haven't really had a problem with any SD/microsd card in some time, so this one works fine, but I don't know if that's saying much
• The HDMI cable's fine. Typical generic HDMI cable. Reliable, but if you already have a spare, there's no reason to use this one instead

So, here's my advice:

• If you eventually decide to buy a kit, that's definitely the one to get. If you'll make use of every piece, it isn't a terrible price
• If you want to go with individual parts, heatsinks probably wouldn't hurt, get a reasonable case (just to keep dust out), pick up any microsd that's at least 4 stars on amazon, and make sure you have a good power supply. If you want a 'set it and forget it' level of reliability, that's really all you need to focus on