Because people were asking for it as much as 10 years ago!

If that could be done then fine, but most touch screen devices don't give you that option (read mobile phone here) which can make them frustrating to use, particularly with tiny screens. I guess the K-1 isn't aimed at those who are used to using touch screens on smartphones but to an older profile. Mind, the Canon M doesn't have a viewfinder whereas the K-1 does so their screen has to be on just to use it. Its designed to be a compact portable, their answer to the Q.

Personally, I'm pleased they haven't made it a touch screen. It would have added to the cost, made it harder to use for those not used to such things, possibly slower to use (ie inadvertently altering the wrong thing and having to put that right before doing what you wanted (and repeating your error several times first!) They also tend to use more battery power and you couldn't, for instance, shoot with the screen off.

I can't see any real value in the way the screen is articulated. I think I'd be happier if it was more like the MX-1 or hinged at the side as other males have done. It does look a weak point in the design but I'll happily be proved wrong.

Do we know yet whether it will meter the older K & M lenses at full aperture, or will it still need to stop down first as per the K-5 and K-3 etc.?

To my mind, any lens from a fisheye up to as long as you can get can be used for landscapes. A photograph of a range of distant hills taken at 200mm is just as much a landscape as a standard view taken with the kit lens at 18mm. So to answer the original question.; any lens you've already got will do fine!

Those primes are faster = bigger heavier glass.
No current Pentax 400mm though there are some in the back catalogue (eg SMC Pentax-A 400mm F5.6.) The 300mm I mentioned will give you better images than a third rate 400mm that can be cropped. 400mm primes will normally be quite a bit heavier than I suspect your 75-260 is unless it has a very small maximum aperture. I suspect you find that images taken at full zoom on your present lens are not particularly sharp. Using the prime 300mm you'd be amazed at the difference!
If you want to go longer than the 300mm for a current Pentax lens then there is the Pentax-DA 560mm F5.6 ED AW. But that's very specialist, more suitable for birding than bears. But you're looking for around £3K for it. Even a 400mm is still quite long and you may often wish it would zoom out a bit - tricky for a fixed lens!

Without spending a fortune, have a close look at the Pentax 55-300mm.

Would your ideal lens be in the range of your current zoom or are you after something longer? Are you after a prime because that zoom is too heavy? If so, not all zooms are. Or is it that you want better, if not top notch quality?

The lens that comes to mind is a Pentax SMC DA* 300mm f/4 ED SDM, or perhaps the SMC Pentax-DA* 200mm F2.8 ED [IF] SDM if you want something within the range of your present zoom. They're fairly pricey (and not particularly light, but great quality though.) The HD Pentax-DA 55-300mm f/4-5.8 ED WR is an alternative zoom lens with a good range and not particularly heavy (lighter than the two DA* primes.) Also worth considering is a Tamron or Pentax 18-250 (discontinued) or a Pentax 18-270 (also made by Tamron) which can be used as an everyday walk around lens, but with a good reach. Don't overlook the Pentax 50-200 f4-5.6 either, that's quite light and affordable. I appreciate some of those are not fixed length, but you really need to work out the focal length you would prefer if a prime is essential. Having already got a 75-260 to play with you should be able to workout what focal length would suit you best, and then work out what you can afford.

Some of the more affordable primes are the older M and K series primes from the film days. Some of these are manual focus, but we managed with them before autofocus was invented! As to what focal length, that is really something only you can decide.

Should keep one warm in bed if used to replace the hot water bottle.

When you say it crashes, do you mean it locks up or really crash to the blue screen of death?

Are Firefox add-ons up to date?

No problem here with Win7 and Firefox with Adblocker

Suggest if it carries on like that, reset Firefox to default.