The best wildlife lens is either the 500mm or 600mm prime lenses by Canon (one N in canon). Canon has redesigned both lenses to be lighter and can be hand held by more people than before. Yes, these are expensive. Your second best choice for wildlife would be a 300mm f/4 lens with a 1.4 teleconverter used on one of Canon crop sensor bodies like the 7D, 70D or wait for the new 7D Mark II. The 400mm f/5.6 isn't a bad choice either. Last would be an aftermarket lens like the Sigma 150-500 and/or their new or soon to be released 150-600mm lens.

Cony, definately a tough situation. I too own the 5dmkll. I tried to do birds with a 200 +1.4x and just didn't get the reach. A small bird(robin size) at 30" is just too far. I went to a 100-400+ 1.4 and am happy with what I get. You still have to be close, that is key. If you crop more than 50%, you'll loose the details completely.
You could get away under a $1k if you got the converter and a used 7d, that will get you the's out the length of the Sig(since they are short), with pretty good IQ. But the reality is that you need to be close enough to fill as much frame as possible. I feel if you manage 10 good shots in a year of birds, you are doing VERY well.
For more money, you can go the 100-400, or 400, +1.4's. You need to tape the pins to get AF.
I personally have not seen any shots that would convince me to try a third party lens, or maybe they are just miss-used. And the big primes aren't magic, but the prices are. My 100-400+1.4 does pretty well. I have not used a 2x, but want to try one.
So what am I comparing it to? I used to used a 500 f4, and until I replace it, I use a 600 f4.5 manual on occasion.
Cony, good luck. ;-)
SS

For taping the pins on a Canon lens to achieve autofocus beyond the design imposed f/5.6 either use the search at the top of the page or go to http://www.uglyhedgehog.com/t-126721-1.html

Before taking the expert word of any poster on uhh in deciding an issue such as this, in lieu of renting the equipment in question and testing it myself, I like to go to the profile or posted urls to websites of those commenting and look to see the quality of their work. If a person shows that their work backs up what they say then I'm more likely to accept their advice. If they've shown no work then I view what they have to say as "you're on your own" because "I'm happy with what I get" says NOTHING since we don't know what makes them happy.

A member of uhh and a long time photographer who has not posted in this thread but who has recently received some international recognition for his work. He mostly shoots with a 300mm and a 1.4X is SwampGator. I would refer you to the threads he has stared and the images posted in those threads. He also has a website you can look at:

http://www.uglyhedgehog.com/user_topics_listing.jsp?usernum=6711&page=1

http://phillanoue.com/

I wouldn't exactly say the 60D is "much" better for wildlife. I'd say if all you are after is more reach, then the 60D would be the better choice. I use a 7D with my 500mm lens and a 1.4x when I have a situation where I need the most reach and have good light. I use my 1D mkIV (1.3 crop factor) for most everything else since it's got a 10fps shutter, and good but not great sensor and I use with with all my lenses. I use a 5D MkIII (FF sensor) for situations where I know I will be shooting in low light conditions and don't need the fps. It has the best sensor of all the bodies I own and is best for low light. I also use it for landscapes and portraits.

So as you can see, there really isn't a best camera for all situations. If there were, I'd probably only own one body. Cameras are kind of like shoes. There are running, walking, and dress shoes. Then there are specialty shoes for each sport. There are casual shoes for cold and hot days. There really isn't one shoe that will do it all.

Who are you talking to here and who are you talking about? If you would please select the "quote reply" button it will include the post you're responding to and make it clearer what you are saying or asking.

If you were responding to my post about swampgator, the point of my post was to address the question of whether or not a 1.4X TC ruins a persons images. I think this shows that it doesn't hence there wouldn't seem to be a reason to avoid using one which is counter to what a couple of posters in this thread have stated. I use one an awful lot but then my images aren't anything to be held up as a shining example of what can be achieved when using a TC. I'm sort of proud of some of my images but then I'm no swampgator. As to the settings swampgator uses, I imagine they're all over the scale. He may have some settings he starts out with given certain conditions. You might send him a pm and start a discussion with him about his technique.

Imagemeister is also a prolific shooter who uses TC's in his work with fantastic results. You might like to look at his images here on uhh also, or on his website.

http://www.uglyhedgehog.com/user_topics_listing.jsp?usernum=8242&page=1

http://fineartamerica.com/profiles/larry-nieland.html