As mentioned earlier, if you want a screen protector but don't want to lose that signature feel of the glass display on the iPhone 6, then getting a tempered glass screen protector would be perfect for you.
Tempered glass screen protectors come in thin sheets of glass that you simply affix atop your iPhone's screen. They're a bit thicker than regular plastic screen protectors, so the Home button may feel more recessed than usual, but that's something you can easily get used to.
One thing to be aware of is that tempered glass is a bit more expensive than other screen protector options, simply because it's glass and not just plastic, but it's highly worth it if you want to keep that premium glass feel when using your iPhone 6. Another thing is that since the edges of the iPhone 6 display curve down, tempered glass protectors won't cover the entire screen. This may not be a big deal to some users, but it could be annoying.
Since the iPhone 6 is still fairly new, tempered glass options are a bit scarce right now, but this one from Tech Armor will do the trick until more options are available.