How to spend my next $1k or $2k??? - a little help please.

[Sheiky]

To help reduce the number of frames where the camera picks exposure poorly I have gone to manually setting exposure during warm-ups and for this rink 1/500 f/3.2 ISO 1600 got me these. I also preset the WB using an expo disk so that all that is left to do in PP is to crop.

Those settings are actually not that bad. The ice-track I shot at about 3 weeks ago is fully covered. It does however have some sort of tent over the track and it seems to be letting in just a little bit of light. I could manage to get 1/1000 F4 ISO-3200. I have also done a shoot in open air at night which was a complete different story. If you want to see, here are my latest shots at the ice-track.

I attribute the softness to the Sigma and the noise to the Rebel XT. Though it could be that the two resolution of the Rebel XT is also hurting.
I also worry that no matter what camera I pick the Sigma will always be soft.

The noise is definitely the camera. The sharpness is not necessarily the Sigma's fault. Although the Sigma will probably get significantly better stopped down.

I worry about the 70-200 f/4.0, not that it's not a good lense, but given that I often am shooting in the 2.8-3.5 range that I won't be able to get the shots I am now.

I am using the 5D2 and 70-200 F4L IS for these shots. Personally I'd rather have the f2.8 lens for these indoors things. But I rarely do this kind of photography so I can live with F4.

I have been on the fence on the 24-105, I like the IQ I have seen, but on a crop body I worry about the lack on the wide angle end of things. Also, I am pretty happy with the IQ and range of the 17-85 I have.

If you're happy with the 17-85, just go with it and put your money in the places where you can benefit the most.

Apart from the sharpness of your Sigma and the noise of the 350D. You will notice a major impact when buying a faster body. 40D and upwards. The lag between pressing the shutter, auto-focus and the actual making of the photo will decrease quite a bit and that is very noticeable in sports-photography.

And the best thing about this all. You don't have to justify all the expenses to your wife. She seems to like your hobby