What lens to buy?

I'm travelling to India, Nepal and Thailand. And I'b bringin my EOS350D with me. Currently I use the 18-55mm that comes with the camera, but I want to be able to reach longer, up to 200mm. Sigma has made an 18-200 that I would've bought, if it were'nt for the fact that they are comming with the same lens with OS. But I'm leaving on the 6th. I'm ranting here, down to buisness:

1.Buy a rather cheap 55-200 Sigma now.
- I have to carry two lenses and switch between them. Takes a bit sharper pictures.

2.Buy the 18-200 without OS now. (double the price of the 55-200)

3.Wait for the 18-2000 OS sigma, but when will it come? And how much will it cost?

I can't make up my mind!?

[ Edit: Edited at Nov 16, 2006 4:12 AM by Olof ]

Olof,
Looks like you have set your heart on a Sigma lens.
The standard 18-55mm lens is a very cheap and although the pictures taken are ok, the quality is substandard when compared with higher ranged lenses.
OS, i take it you mean the image stabilized lens, at 200mm it's a nice thing to have but there are ways you can get around it (use of pods -mono or tri) increase the iso speed.
I personally would go for the better optical quality. I use a 70-200mm L lens on my 20D with no problems, and being an L lens it it a heavyweight.
Image stabilizing is a nice luxury to have and will gain you an extra f. stop.
Canon have just released a 24-105mm IS lens which is f4
and a s-lens of 17-85 is f4-5.6 might be worth looking at.
The Sigma lenses i've played with are a bit noisyer than the canon and the focus a bit slower, opticaly they are pretty much equal (depending on cost).
An honest opinion i'd take the wider ranging lens to save the hastle of taking extra lenses and the changing out of lenses.
hope this helps a bit.
Jase

Thanks´! that makes it a bit more clear. I'll write here when I've made up my mind. Money is always a factor. Its not good buying cheap and getting something useless, or buying something expensive that's not worth all the money, you can make a bad choice either way.

[ Edit: Edited at Nov 18, 2006 2:16 AM by Olof ]