Thanks y'all for a very helpful discussion.In your position i would get the sigma 18-35 f1.8 first it looks like a perfect match for a 70D IMO and your 28-70 covers the longer end nicely with a bit of overlap
I ended up buying the 70D on Amazon (body only) and got it for $999 (well, $890 since I had some Amazon points to blow). For the money, I think it'll be a great camera for what I do and hopefully last me at least 8 years like my old trusty Rebel XTi did.
I'm also going to continue to save up for a better lens. I'm not sure if I'm ready to move up to an L series, but right now I'm mainly using a Sigma 28-70 f/2.8 and a Canon 60mm macro. Which are good (especially the macro) but I'd love to get a lens with a big wow-factor eventually.
Anyway, thanks again for all of the help!
and for the money Id grab the 10-18 IS canon STM to cover UWA