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You could go much higher in ISO than 800, with a good noise reduction software (such as DXO or Light Room) ISO 3200 is quite usable. Much better to have a noisy shot than a blured one. I have taken properly exposed shots up to 12,800 on my 60D (same sensor as your t2i) and it's still good for web sized images, actually it's quite good at that resolution, and a kinda noisy 8x10 but not bad.
John.
Here's another vote for not being afraid to use your high ISO. I have a 7D, same sensor as your T2i, and I use 3200 all the time. Unless your printing larger than 8x10, then your fine. Get some noise removal software and your set. I used noise ninja when I had windows and wish they would update their processes for newer macs. I use topaz denoise and it works really well, just much slower. The other thing for slower shutter speeds with non-IS lenses is work on your technique. Always make sure your steady to get the best possible shots which means good stance, good posture, and good arm position. Read up on Joe McNally and his technique for taking photos at slow shutter speeds.
As a sample
https://lh6.googleusercontent.com/-V...G_5006-001.JPG
this was shot at 3200 iso, f/8 , using my t2i
although not intentionally chosen you can see it's nice enough to share and use on the internet.
at 100% it does loose a bit
https://lh3.googleusercontent.com/-x...G_5006-002.JPG
another factor if your worried about noise might be image size, I use the RAW+Large Jpg setting 18M 5184x3456- possibly cleaner than using a medium jpg
-I'm still new to this (about 4 months) of not just point and shoot full auto, so there was no noise clean up in that image.