Help with tele lense choice please

I have a 300d with the kit lense, i think the kit lense with keep me going for wide and possibly macro for a while. Eventualy i will replace the kit lense.
In the meantime i want a tele lense for nature shots etc.
Ive shearched the forums but it all gets a bit confusing for a begginer. I 'think' the canon 75-300 is off the list as i have seen comments about it not being very sharp.
So i have made a small list --

Canon EF 100-300mm F4.5-5.6 USM
Tamron 70-300mm f4 - 5.6 LD
Sigma 70-300mm F4-5.6 APO

Out of these, which would be the best choice for usability and image quality?
Are there others i should consider?

I dont want to throw to much money at it, so the above canon is around the most i want to spend at the moment (~230UKP).

Advice much appreciated.

Hi Penance,
I have a EF 100-300 and it performs pretty good for the price (bought 2nd hand). When there's enough light (sunny day), the image quality is great, especially at f8~f11 range. I have heard and seen good images taken with the Sigma APO 70-300 Super II too. It seems like a decent lens, and it is very economical. I'm not familiar with Tamron lens.
If u want some samples taken with the 100-300, without any post processing, let me know.
Good luck.

Hi cfcRebel,
Thanks for the reply, if its not much trouble i would like to see some sample images.

I would go for the Canon 100-300 USm or the Sigma ... I think they're pretty close. Which ever pops up second hand would be my approach: if buying new then the Sigma is a lot better value. Around £140 when I last looked via 7dayshop. SH they go for around £95

thanks condyk, i hadn't thought of 7dayshop. Certainly cheaper.
The 100-300usm is 189.

Sure. I'll post some here when i get home from work. I can only post the resized version to fit the 100K limit. PM me if you want me to email you the originals instead.

I don't know if the price in eBay UK is as low as the ones in eBay US but no harm to check.

PM sent