I agree with tfc111601. I carry an EB-LS on a drop rig with my field gear. If I'm wearing civies or doing more "humanitarian" missions in counties where the local government doesn't want to make a big deal of our prescence, I'll carry the folder only. I used to carry a larger knife (by another maker) on my LBE, but I found the larger size actually didn't help. Now, I carry the EB-LS, a Gerber Applegate-Fairbairn combat folder, and a Gerber multi-tool. That's all you need really. Feel free to substitute the combat folder for an AR or GB. I've got a GB, but I personally like the Gerber's 4.5" blade. There haven't been many knife fights that I can remember, and most of the time you knives get used for things other than fighting. Given that, why do you need a 7" blade? My two cents.
Are you a new soldier, or returning to AD? If you are part of the conventional forces, most commanders and first sergeants look real hard soldiers carrying their own large fixed blades beyond the M-9 bayonet (and that's if you're infantry). I can't speak for the USMC, but I think they'll agree that anything but a K-Bar is skirting the boundaries. If you're any other branch but that, they look even harder. Before I came to the dark side, I had kittens when my soldiers carried big blades (partly why I also got rid of mine; something about practicing what you preach...). Let's face it, we in the military tend to be more conformist by nature...you'll look extremely out of place in a conventional unit with a big knife. Small fixed blades and folders are they way to go.