Hi PWD,
This was a question I thought about a lot when I was looking for an all round rifle. Because I wanted to do some long range varmint shooting, primarily coyotes and wolves, I opted for a heavy barrelled rifle, but since man does not live by varmint hides alone, I also wanted a calibre capable of taking deer, elk and moose at shorter ranges.
In the end I bought a Remington Sendero in .270Win and mounted it with a Leupold Vari.X III 4.5-14X40 scope. It is a heavy rifle but I do shoot 1/4" groups at 100 yards with it and it is deadly. We have a lot of gophers here in Alberta and the ranchers are desperate to exterminate those pesky critters. Anyway the Sendero does a nice job on gophers out 200+ yards.
I'll admit that a .270Win might be a bit much for gophers, but it's fine for coyote, wolf and deer. I've been told that it's possibly a little light for elk and moose but as far as I know, lot's of elk and moose have fallen for a .270 so with proper ammunition, I'm hoping to fill my moose tag this fall.
From the response of the other gentlemen and for the type of shooting that you would be doing, you can't go wrong with a .243, although I would also suggest looking at a .22-250.
Which ever way you decide, if you want to do some target and varmint shooting get yourself a heavy barreled rifle in the calibre of your choice.
Let us know what you're getting.
Cheers and Good Luck,
Rubber Ducky
p.s. For some reason, Remington has discontinued the Sendero in .270Win. Nevertheless it is a fabulous rifle and it's still my favourite (only) rifle.