I'll call it "value", which is a combination of most of the above virtues with price.  Bang for the buck, so to speak, the ratio of what-you-get to what-you-paid.  The "bang" should be a reasonably powerful cartridge, decent rate of fire, accuracy, reliability, and 'coolness' factor say historical significance.

In my estimation, a lot of milsurp rifles do really well in this respect, especially when one takes cost into account.  The SKS is an example of what I mean, being tough, reliable and some of them aren't bad shooters at all, for a decent price.  That's still true even with them being over $300, but these things were really king back a few years ago when they went for $100-$150.  I read that less than 10 years ago they were going for $60 and a thousand rounds was another $50 or $60.

A close second for an "average guy" would be a CMP M1 Garand for about $600.  It costs more but wow look what you get.  I don't know how to put a number on how much you "get" out of an M1 compared to say an SKS, surely it's more but how much more firepower, accuracy, or whatever?  Ballpark personal swag, I think a CMP Garand is an even better bargain than a $300 SKS, though it costs twice as much.

The acme of value rifles would have to be the Mosin-Nagant.  Value, power, definite reliability, and absolute toughness in a budget package.  You just can't beat getting a 30 cal rifle for less than a hundred bucks.  Mine's an M44 I picked up on sale for $59 a few years ago.  I don't shoot it much because I don't like having to shoot ammo I didn't reload, but it's a fine enough rifle for a lot of uses.