Searching For a Great Portrait Lens

A few days ago I suddenly got the feeling of "getting" the point of the fast zoom lens. The Canon and Nikon people have these great lenses that are 70-200mm/2.8 or thereabouts, and I never really got the thrill. Hey, I have a 70-300 macro that's just fine thanks, and it cost me $60 at a swap meet and it doesn't require an assistant to lug it around, what's the big deal... ?

Oh yea, the "f/2.8" part :)

So I got it in my head that a good or great portrait lens would be awesome to have, and being able to shoot shallow DoF portraits from distant(ish) distances was a new goal. Maybe this is what has been missing in my people photography? Course, having a budget I also tend to chant the following to myself:

Buying new gear will not make me a better photographer,
Buying new gear will not make me a better photographer.

But if I were....

Let me say that the site Pentax Photo Gallery is both brilliant and evil. Brilliant for giving a forum for Pentaxians to show off their (peer selected) work, and evil for allowing people such as myself to browse images by metadata and see a set of amazing images by a particular lens or camera.

So I have been looking at the following lenses:

• Pentax FA 77/1.8 Limited - by all accounts one of the best lenses from Pentax ever, full frame (for when Pentax releases a FF DSLR), but expensive and limited to one focal length (though it's a good length for portraits). PPG Images, BH info page, luminous landscape review.
  
• Pentax DA* 50-135/2.8 - Digital optimized, so not full frame, covering a nice set of distances (75-202mm in 35mm) for portraits, though I haven't heard much about it's quality (though I'm sure it's great). Also expensive. PPG Images, BH info page.
• Tamron 70-200mm/2.8 - I was surprised to hear that this came in a Pentax mount, and have seen and heard nothing more about it, other than seeing that it's also in the $700+ USD range. BH info page.

That looks to be about what there is out there for high end, bright portrait length lenses. Based on the fact that something like 80% of the images in the PPG site for those lenses (well, the top 2 anyway) were portraits (and great ones at that) that would indicate to me that I'm looking at the right ones. Course, other suggestions would be great too.

Course, there's also this little DA 10-17mm Fisheye zoom that I've been looking at... With pictures like this gorgeous one (and others if you click back and forth) that show none of the screaming "hey look, it's a fisheye!" look that you can get makes me think that could be a really fun lens to play with.