If you asked a 1000 people who really know their stuff:
Rem 700 is #1.
Savage is #2 and a lot cheaper.
(I'm not counting custom stuff)
.223 would likely be your best choice for short and mid range because it is the most common, cheap, versatile, most widely supported.
The Rem700 VSSF may be your best choice & one I want. However, it is very pricey.
Another choice would be a well used Rem700 & buy a custom quality barrel.
Another is to visit some of the for sale lists and buy a used Rem700 that has been highly customized & accurized for a tad less than the VSSF. If you want web links to this last idea, email me. This last choice is what a lot of varmint / benchrest guys recommend.
If you want to reload & do the old gun / new barrel, there is .223AI for a tad more power. I think there are new WSSM in .22 cal just comming out, but that would kill a lot of the good things about .223. ie, cheap, common, etc. I want to find out if you can have a 223AI made and shoot store bought ammo in it to fireform without any risk. That way, you could shoot storebought all the time and then reload 223AI and build up your supply of loaded ammo in that chambering.
Another reason to stick with .223 is that it is a mild chambering & therefore your barrel will last far longer. If you shoot .22-250 or 220swift and shoot a lot of rounds at targets or prairie dogs, you can eat up your barrel.
So, get the Savage or Rem & buy ammo with good brass to save up. Free-float it & bed it as mentioned when time permits.
* I spent many hundreds of hours on benchrest.com when I was going to do a custom rifle. Also, there are a variety of varmint web sites. For a real evenhanded discussion from another source, I like a former benchrest shooter & varmint dude turned reseller. He has a discussion of your choices in his cataloge:
www.kinneman.com
Here is where he discusses his "RemBR":
www.kinneman.com/Page 2.html