Hi there! Just to share my thoughts:
I had a 500D a few years back(About 2009?), Went through a 7D(My sister's) and just bought a 5d2. On the time i was with a crop, i only had Non L Lenses to work with, 18-55,55-250, and a 50, then upgraded to a 70-200L II, then had the 7D. I was deciding on this also because i think that the 7D really suited the part of me that wanted to get fast action. But my heart still was on landscaping.
So i bought a 5d2 + a 17-40L( So now i have a 5D2, 17-40L, 50 1.8, and a 70-200L II, and a 7D that i can burrow anytime.) As a Amateur switching from crop to FF, I was shocked out of the very first snap i took out of the 5d2 with a 50mm 1.8, and i was at a loss for words. After that I've only been shooting with my 50 and 17-40 for landscapes. My 70-200 was ignored for a while. I love the 50 on the 5D. I've learned to love the nifty fifty more now than when i had a crop body. I haven't tried a 50 1.4 (But im very excited to, alot of people are defending it), but the 50 1.8 is just splendid.
Just experience from an amateur
hope i helped. Good luck on your purchase!