I use a Cabella's fishing bag that I got on clearance at their outlet in Springfield. It has very heavy duty handles and strap, and easily carries all my crap plus 5-600 rounds of rifle and/or pistol for big range days.
I bought a double rifle case from academy called Draco gear or something like that. It is awesome. Had so many pouches it is ridiculous. And the Rifles fit very tightly. Very nice bag. Can easily carry two rifles and pistols as well. It we about $70.
An Emdom TNT Bag that i came into on a smoking good deal a number of years ago. It's worn like iron and can carry LOTS of stuff. Eight rifle mags, tool kits, another concealed pistol and more. I had a local stitchbitch buddy mod one of the side pouches to hold a trauma kit.
I use various Maxpedition bags for competitions because of the nice shoulder straps. For regular range time, I use a 5.11 bag that has two padded pouches on the left/right side and a large open area in the center. Sometimes, when I'm feeling particularly froggy, I use a 5 gallon bucket from home depot.