People shooting different ways is a good thing. I actually have a Tamron 70-300, I just don't use it for anything serious, mainly just family snap shots when I can't get close. Although my neighbor does enjoy it when I use it to take photos of her farm animals
I would like to have a 70-200 f/2.8 for less any your face portrait work though. For a good example of how people shoot differently take a look at this video:
ShutterSpeed Episode 01 | Nic Fillingham | Channel 10
Fast forward through the first 20 mins, it's all technical talk for newbs, but then they interview Phil Borges and he shows off his gear and gives away some of his tips. Given, he's a portrait photographer, but he mainly only shoots a few small primes and then he has that Canon 24-105 F4 L lens that he uses for framing (must be nice to have a $1000 lens for framing purposes only).
As far as the K20D goes...if it drops down to $1000 I'll most likely go with it instead of the 40D; but it has to do it before July because I'm not going to miss out on this 40D deal. My ideal kit would be the Pentax K20D + 17-70 f/4, then either the 50-135 or the Sigma 70-200mm HSM. I don't need a ton of range, but I do want good quality and low distortion in the range I do use.
Again though, megapixels don't mean a whole lot to me aside from giving me more cropping room. A 6 megapixel image printed 16x20 looks fine. And according to this test is indistinguishable from higher megapixel images by 47 out of 50 people:
http://www.nytimes.com/2007/02/08/technology/08pogue.html
Besides, I used to work as a Photoshop expert for a large format decal printing company. Up scaling images 35mm images to fit on huge trailers used to be my job (see attached). You'll have to excuse the quality of the finished photo, apparently that was the best the applicators could do when they finished.