Well, you seem to be doing very well with the "fantastic plastic", so why not stick to what works? Cheap primes: 28mm f/2.8 is only $250 and will be perfect for pulling in a lot more of the background while staying close to your subject. As Robert Capa said,"If your picture isn't good enough, you're not close enough." A wider lens will help you get closer.


Next I'd suggest the 100mm f/2. This is a much different angle of view from your 50mm, but it's still very fast and excellent for portraits. It's $450.


Third I would advise an upgrade for your 50mm. The nifty fifty has a very bad focus ring, terrible build quality, ugly bokeh, and other disadvantages. I suggest the Sigma 50mm f/1.4 as a replacement. I think it's better than the equivalent Canon in everything except perhaps autofocus.