Hi guys - I'm gonna have about $2K to spend in a coupla months, and I'm *really* thinking about picking up the Canon 70-200mm 2.8 IS lens. OR - I'm ALSO considering just getting a Sigma (or Tamron) 70-200mm 2.8 lens, and having about a grand to spend on other stuff along with it (maybe a Sigma 24-70mm 2.8). You can see in my sig below what I currently have. So, my question is, is the Canon THAT good that it's really worth it, or would I really notice the difference in my final pics? Rrgghhhh.. Been struggling with this. Let me know your opinions - thanks guys.