Hi Guys,

Sorry if this hase been discussed previously, I have searched through the forums but cant really find anything...
I have a Canon 550D body with a few basic lenses...
What I have is the canon 75-300mm crappy non IS zoom lens (bought secondhand for $70), I have been playing with a mate's 55-250mm IS kit lens and an really blown away with the IS, even if the lens itself is not all that crash hot...What I would like to do is get rid of my lens and get a decent zoom lens without going as far as say the canon 70-200mm f4 ($1500). I do not tend to use the zoom lens a great deal except for dabbling in some macro and the occasional motorsport/wildlife shots
I already have the 17-85mm general zoom lens, so just need something for the zoom stuff and something I can use with extension tubes to get some macro shots. I looked at Canon 18-200 IS (but no USM), then looked at a range of Tamron and Sigma lenses roughly around $500-$700 but these all seem to be the super zooms 18-270, 28-300 etc and just seem to much of a compromise in image quality...
So after all the research I'm back at square one and am thinking of just buying a 55-250mm and maybe a dedicated macro lens later on (canon 100mm macro)
What does everyone think? Is there a cheaper upgrade option? Are the Tamron/sigma lenses any good?
Essentials: reasonably fast focus, image stabilisation, under $800
Non essentials: fast lens (not too much low light stuff going on)

Thanks in advance!