Which ISO ranges do you use indoors w/o a flash

Now that I am using a light meter to shoot with, it is giving me reading that I may not have considered before using ambient light only.

I would rarely shoot at ISO ranges above 2000 ISO due to noise. Although I can control noise very well using lightroom.

Is it possible to shoot in the 2500+ ISO range and still get sharp photos?

I shoot 3200 often during receptions.

It really depends on your camera. While all of them have higher ISO settings, they are certainly not equal in terms of performance. I can use my 5D at 3200, but have to be very careful as there is little exposure latitude at that ISO for missed exposure. My 40D struggles to please me at 1600.

Yes often ISO 1600-3200 is the go for me during receptions and parties and indoor events

As I use all prime lenses typically wide open, sometimes I can creep down to ISO 800 or even lower if I'm lucky or the venue is brightly lit. Extremely rare though.

Regarding ambient light only, these are crapshoots, I've had to do shoots at like ISO 12,800 equivalents (3200 pushed 2 stops in DPP) with f/1.4 and f/1.2 lenses! Very noisy, very soft and only good for small output (i.e. websize)

I'm ok at 800, but am very nervous at 1600, on my XSi.

I upgraded to a 5D2 from a 40D and 400D (XTi).

At ISO 1600 the 40D is a smidge better than the 400D. But the 40D is pretty much the same as the 5D2 at ISO 1600.

The advantage of high ISO capable cameras like the 5D2 is that if you underexpose at ISO 1600, you can easily recover the shot by pushing 2 stops in post. If you try that for the 40D the file turns mushy, soft, magenta and crazy noise filled

But at a baseline ISO 1600 amount without any pushes, there is little, if any difference between most cameras newer than the 400D (Xti).

I won't shoot above 800 with my 40D...don't like the results

I use 6400 on my mk3 fairly regularly, and have used 12800 on the mk4 quite a few times
I would not hesitate to push the iso to H3 on the mk4 if I really needed the shot, although printing on newspaper hides a bit of noise

I generally use flash to fix poor light quality, rather than light quantity now I have the mk4
Back when I was shooting with a mk2n I tried to not go past iso1000 if I could help it

12,800 on my 50D if required

I turn off ISO a lot of the times. It can help in some situations!