So, thank you to everyone who gave their positive and not so positive feedback. It is greatly appreciated.
I do, however feel, that somethings are being assumed here and maybe it was my wording that led to it.
Last night, when I posted I was mad/disappointed. I thought I took some great shots (judging from the back of the camera), with the light I had, so when I got home I was severely let down...which may be why I just made my first post in this thread so short.
This wasn't "my" client... I am, I guess what you would call "second shooting"??? behind another photographer who is letting me. She told the client that we were out of light, but I wanted to try and take some pics with my ISO up (because they were looking so good on the back LCD of my camera). The photographer and client had already established a new date/time to meet to take more pictures, so this picture I posted up was one of 5-6 that I took in that light (I just picked it because all 5-6 were just as grainy...naturally).
As for the lens that I purchase, I appreciate the kind words that you guys think I'm labeled a "professional" photographer (sarcasm), however, I've done as much research as I could when it comes to buying each lens and would like to work with the best that I can get my hands on. My thought process behind it is, if you were learning to play basketball, would you want to learn from a high school coach or Kevin Durant?)
As for other, more helpful posts, I do appreciate it and realize that I need to basically leave ISO alone and really learn to "master" shutter and aperture first.
So, as a general rule of thumb, what ISO do you not go ABOVE? Or is there even a general rule of thumb (should have been rule of wrist) for this?