I like my bags discrete and of fast access backpacks ar not an option for me. 3 lenses are more than enough for me... im not a body builder...I use the lowepro classified 160 and its nice and discrete the 140 version would also be a great bag.
On the 160 i can fit the xe1,35, 50-230,18-55 flash triggers a mini tripod batteries and cards theres room left for a tablet if necessary.