Help requested in EF zoomlens choice!

[TrueLoveOne]

Long distances and telephoto shooting is not really my thing, but on some occassions it might be handy to have something in the range 70-300mm.

Since i will not use it a lot, i do not want to spend huge amounts for Canon's L lenses, so i am looking for the best choice on a budget.
I've been looking on flickr, pixel-peeper and several other sites that review Canon EF lenses, but i can't really pick one....

So, fellow shooters, i am curious about your opinions and experiences!!

Lenses like Canon 70-300, 75-300, 100-300, Tamron 70-300 or others, please give me some advice!! If there's a more or less better or outstanding lens available with a range of 70-200 or something likewise, i'd like to know too, i'd rather have 100mm's less and a better picture than the 300mm's on the long end!
I read most old Sigma lenses have either gear problems or do not work on the 5D, so i think these are not an option.

[calvin83]

Only the expensive super zooms can have excellent result on the tele end. The Tamron SP 70-300mm f/4-5.6 Di VC USD is still the best affordable tele zoom in your range with good vibration Compensation and decent macro (1:4). It is not very good at 300mm but you cannot find any other better zoom in the same price range. I see lots of people here using this lens on their Canon camera.