Get the Garand. While there are newer rifles out there such as the AR-10, FAL and M1A, none of these can match the nastalgia and history that goes along with the Garand. And the beauty of the Garand isn't that it just happened to be the rifle we used during WWII and Korea....any rifle could have been there. But what makes the Garand so special is the fact that the gun was damn good at it's job and served with distinction...just like the men who carried them.
Also, stay with the 30-06. While standardizing your ammo is generally a good idea, I think changing the ammo of this wonderful rifle is nothing but a pure bastardization. There is still plenty of good quality GI ammo available at the CMP also, and you can always reload or have someone load you some ammo to M2 ball specs. You aren't as likely to gobble up as much ammo with the Garand as with an AR, AK, etc. anyway. The slower rate of fire and heavier recoil helps to keep rounds fired in the sane category. Plus, if you need really accurate ammo, Federal Gold Medal loads a 168 gr match grade round that should work well.
Again, there are newer rifles out there that are lighter, fire more rounds and look more futuristic. But when it comes to quality, I would take a Garand over any of them. There's a reason why the rifle weighs 9.5 lbs and when someone sends a negative comment my way about my M1's weight, I just chuckle and inform them that I am holding 9.5 lbs of confidence. A heavy duty, robust rifle that delivers 8 rounds of potent 30-06 accurately and quickly....that still seems good to me, even with modern "assault rifles" everywhere. I too like the M1A from Springfield. But what I don't like is the cost of the 20 round mags. They are fine rifles but I would would rather just spend a small amount of money and get gobs of 8 round en-bloc clips. With practice, you can keep an M1 rockin'and rollin' plenty fast enough with these.