I don't know what lenses you have now, but be aware that all of the lenses you're considering are relatively large and heavy. I have the 200mm f2.8...it's a great lens...but it sometimes gets left home because of it's bulk. I could say the same for my Tokina 80-200 f2.8, too. I wish I had one of the modern Pentax telephotos so I could tell you how they compare in image quality, but I don't.
However, I can tell you how I choose which lens to use. Maybe that'll help in your decision, depending upon your shooting style. If I'm shooting landscapes, where I'm liable to be doing quite a bit of walking and where I expect to mostly be using wide-angle lenses, but want to carry something longer "just in case", I tend to pack my 200mm f4. If I'm shooting something where I expect to be doing mostly hand-held shots and need the reach as well as the extra speed, I pack the 200mm f2.8. If I'm shooting somewhere that I need the reach of a telephoto, but I'm able to use a monopod or tripod, I bring my 80-200 f2.8. Hope that helps somewhat. It's never easy when you're planning on investing this much cash in a lens. Good luck.