What should I do

[Brettus]

Morning all,
Permit me to give you a bit of back story to explain my predicament:
When I got my DSLR (EOS 450D for the record) I only had funds for one lens, I wanted a do-it-all lens so I got a 28-300mm sigma lens. This has recently developed a fault where every picture is blurry with it.

I've since purchased an 18-55mm IS (kit lens) which covers a good deal of my wide angle requirements, I've got a Tamron 90mm macro lens but I could still do with a zoom lens.

I've been looking at (read, lusting after) the Canon 70-200mm F4L IS (same as Bikeramy is selling)
I also considered the non-IS version which is almost half the price. But then there is also the Canon EF 70-300mm f/4.0-5.6 IS USM

IS L £885
Non-IS L £479
70-300mm - £349

I'd been aiming for a second hand L with IS for £600-700 but I'm wondering if I'm just being excessive or if it really is something I'd notice. You guys have seen my kind and level of photography, does anyone have any opinions?
Or should I rent one of the L series first to try, at £80ish for a week, is it worth doing in your opinions?

[Degener8]

What are you looking to take photos of if you don't mind me asking ? I'm guessing with the 300mm of focal length your into sport or wildlife? or are you purely looking for a good all rounder ?

[Brettus]

I like having the reach for times when I need it, I do landscapes, wildlife (mainly zoo stuff though), I'd like something capable of taking to a trackday/event for some fast shots. I'd like to do a little astrophotography but mainly basic shots of the moon and stuff. I guess I've pretty much summed up an all rounder, I've got no fixed niche as such, I don't really do people shots or studio shots but with a zoom lens that is kinda ruled out anyway.

my flickr stream is here: http://www.flickr.com/photos/brettnet

The reason I'm entertaining the idea of the L lenses is I'm wondering if I'm just ignorant of what quality I COULD get, and partially if I'm going to get a lens should I get the best I could afford or is it a case of law of diminishing returns?

The IS would be nice for not needing the tripod quite so much but then the cheap one has that too.

[Degener8]

i looked further a field and went with mid range sigmas, i mainly do sports though to be fair, you pay through the nose on many Canon lenses imo and for general all rounder id probably go to other manufacturers you get more for your cash at the lower prices..

Nice pics btw :)

[Brettus]

Thanks, yeah I'd likely have checked sigma out again now but wondered if by sticking with canon I'd get more out of it, I'm a little disappointed that my sigma failed, I can understand that bouncing round in a top box (in a lowepro bag etc) might have had something to do with it but that is what made me look into others. Perhaps I need to consider third party ones more though.
Thanks for the input

[Degener8]

Anytime mate