I know this is "another upgrade advice" question, but it's always good to get opinions on these things!
I've had my Canon EOS 500D for about 4 years now. It's what really got me into photography in a more serious way, and I've loved every minute of it. But a lot has changed in the past years since the model was introduced and the technology seems to be moving on fairly fast. I am considering upgrading in the near future (it's bonus time soon at work) and I am looking for advice as to the next step. I am certainly not a pro (I don't have time with work), but I always strive to get as close to pro-level photos as possible. I am not looking for a 5D MKIII or anything like that (unless it's very cheap), but the 6D, 7D, 60D, 70D are the kind of things that seem like reasonable upgrades.
I definitely want to stick with Canon as I am used to the functions, terminology .. and I just like them. But more importantly my lenses are all Canon or Canon fitments. I have:
Canon 17-55mm EF-S Kit Lens
Sigma 70-300mm F4.6 DG Macro
Canon EF 100mm F2.8 USM Macro
If I understand it correctly, the EF-S kit lens won't work on the 6D, but I think the EF 100mm is the one I want to make sure I can still use (it's the expensive one).
I primarily enjoy wildlife and macro work, but often find myself in the reptile area in the zoo where light levels are an issue, and high ISO's are necessary. Anything that can help me focus better in these low-light situations is also a bonus!
Any suggestions from others who have made similar upgrades would be very welcome!