I really like the 270 (note the username). It does fine on the elk I've taken as well as mule deer, whitetail and antelope, and also coyotes and other varmints. I hand load for mine, but there are a variety of loads available for it. I prefer the .270 over the .30-06 because it kicks less, is not as loud and the ammo is cheaper.
The .30-06 is no doubt the standard by which all others are judged. It's the most versatile and available cartridge around. There is a huge variety of factory loads available for it, not to mention a galaxy of handloading possibilities.
I see you're in LA, so I'm guessing elk won't be an every year hunt for you, mostly whitetail. When I lived and hunted elk in Colorado and New Mexico and now here in AZ, I've never found a need for magnum calibres to reach out at long ranges, I just get closer. They're certainly not needed for whitetail. I'd recommend the .270, or the .30-06 as a second choice, either would be fine. Or the 7mm-08 or similar would be good, too.
For a rifle, I suggest the new Savages, or a Sako or Browning, Rugers are OK, too. There are lots of good quality rifles on the market for reasonable prices. Not sure what your conditions are in LA, haven't been there in several years and never hunted there. I think a quality scope can't hurt, no matter what your conditions are. I recommend a 3-9X, not golly-gee-whizbang, but it will do anything you need it to do, and at an economical price. Figure on paying as much or more for your scope sight as you do for your rifle. It's much better to put a top quality scope on a mediocre rifle than to put a cheap scope on a top quality rifle.
Hope that helps.