Thanks for the input everyone. I was able to pickup a very nice used 5d on ebay for $585. The prices vary pretty widely on ebay, but I think right around $600 is the most common range. I've only had it for a week, but its already pretty evident that it blows my t3 out of the water for portraits. The shallow DOF and bokeh is great, and while I wasn't super happy with the t3 even at low ISO's, this seems to be much better at 400 ISO than my t3. I haven't had a reason to use much higher than that so far. I will probably upgrade to a "newer" FF at some point, but I don't think I can go wrong with what I spent, and the quality of the photos are great. If you can grab a nice condition 5d, I think it is something to consider if you are using an older rebel and you want to go FF.