Look at what you're doing, what you need, then look at lenses/body and decide which will suit your purpose better. 7D does a lot better with ISO performance than your T1i. Or is faster glass the answer? 10-22mm is a great lens. One serious hangup I'm having about the switch to a FF is the idea of getting rid of my 17-55mm.

So for me it's glass first, again. I'm looking at getting the 16-36mm f/2.8L II and probably the 50 f/1.2L before I'm getting a new body. I will have the ultra wide, the normal, and with the 85mm 1.2 I just bought I don't think I'll miss the range absent from the APS-C zoom.

I say get the glass you'd want to support a FF before making that jump.. if that's the route you wanted to go. (which obviously you'd have to do with your setup, making it a very expensive upgrade.)

If you go the 7D route, you will get the ISO performance, and AF boost in low light as well. I saw that another member on here just posted his for sale for around 1k with less than 8k exposures taken. I suppose it comes down to your budget?