When I got my k10d I got the sigma 105 macro and the kit lens. I plan on getting the sigma 70-200 2.8 macro and 1.4tc. It should be available in march (the old 70-200 is sold out everywhere).

On the Tamron + TC you only be able to use it in manual mode I believe.

For the flash I got the Sigma 500 super + a gary fong lightsphere. It has always worked great even on camera. After the 1.1 firmware update I wish I would of opted for the Pentax 540, as that can now be used as a wirelessly with he onboard flash, the sigma can only be used as a slave and you lose PTTL. I just got an off camera extension, but have not been able to play with it. Here are some flash shots with a diffuser on camera. Hopefully getting it down lower will reduce the chin shadow.Last two were taken with 300d sigma 500, stoffen diffuser