Agree with most of these.
Could suggest the DA 50-200 WR as an inexpensive alternative. If you have to have the 70-200 f2.8 the Tamron version is an excellent lens, I've used it on my k10d and it is very sharp.
The DFA 100 is an excellent macro lens as well. Sigma makes a 105 macro that has gotten a lot of priase as does the Tamron 90mm macro.
The plastic fantastic FA 50mm f1.4, is a excellent value lens, personally I find it a bit too long for indoors and use the DA 40limited instead (even though it's only f2.8) but the FA 50 is one to have regardless.
EVERYONE says that the FA 77 f1.8 is THE lens to have because of its performance, then complains about the cost. Personally, I'd go with the DA 70 limited f2.4, it really is excellent for portraits (you can also use the DFA100 but it's a little harder to use in that application). A cheaper substitute is a Vivitar (or samyang, bower, or other re-branded names) 85mm f1.4 (B&H or Adorama for about $350) manual focus lens. This lens is very bright and works well for portraits and in low light, but is a beast to get in focus with out a split image view finder (after that it works quite well).
While that's quite a lot of glass, I'd suggest you consider on really excellent Pentax lens, the DA 10-17 fisheye. I don't believe Canon make anything like this although I think Tokina does make it in a Canon mount. I really like this lens because it goes from fisheye to ultra wide angle in it's range and is a lot of fun to play with.
Good luck with you lens buying.
Edit: one website you might find of interest as a Pentax speak info site is this one.
http://www.bdimitrov.de/kmp/
The site has a lot of info on Pentax bodies, lenses, etc. and will help you understand Pentax equipment new and old.