hi guys, - would like your recomendations

i have been lurking about here for a while now but never made an account.
i have now though and i would like your recomendatons for me to expand my equipment arsenal.

about two years ago i bought a *istDL with the stock 18-55mm soon afterwards i got a second hand 70-200 f-zoom. i quickly developed a passion fo archetecture and decided i needed a wider than 18mm lens, so i got the DA 10-17 fisheye. i also got a metz 48 af-1 for lighting dark rooms i want to photograph. I have found now that i only rarely use the 70-200, and am either using the fisheye or 18-55.

i was wondering what you thought would be best for me to get. the 12-24 (or sigma equivalent) attracted me because i would be able to aviod the barrel distortion of the fisheye, without processing. it also looks to take very good pictures. downside that it costs so much.

you all rave about the 16-45, and i could probably use the extra 2mm under the stock lens.

i was also attracted to the k7body, because it would be a massive step up from my DL and will work in the cold. on a snowboarding holiday i found it very difficult to stop the DL failing whilst trying to set up a shot for a jump.

thing is though, that i would probably only be able to get one of these, or perhaps the 16-45 and one or two prime lenses.

having only used a DSLR for 2 years do you think that a k7 would be wasted on me with such a short range of lenses?

please tell me your thoughts

i also have a relative who has loads of ex-film pentax lenses that i could try out, although all of them are manual focus, which i find quite a drag.

Remember buildings don't move so manual focus is easier.

Try some of his lenses to see which you like, then look for the equivalent AF one.