Ultimately it comes down to how much you like the game, I mean if I had been as into Oblivion as I was Morrowind, I probably would have shelled out the couple bucks for horse armour. As retarded as that is, I think it's neat in its own way. If I am playing the game a lot, I wouldn't mind putting a few bucks in to it for more crap, even if it's stuff that could have easily been in the original $60 game itself. But I had so much other stuff on my gaming plate when Oblivion came out that I couldn't get in to it and ended up giving my copy to a friend.
Of all things, it seems VERY ridiculous to expect people to pay real monies for something like a single weapon in a single game, but if it was like say a new rifle in Halo 3, despite the massive violent riots that would break out, I beat it would sell like hotcakes.
With Battlefield already being much less fun & popular than it used to be (man, wasn't 1942 sweet when it first came out?) and Bad Company being a bit of a shift in what the game is, I seriously don't see them moving a lot of units of DLC guns.
There is definitely some kind of line being crossed here. There is a huge difference between small expansion/episodic-like content being released for a game after-the-fact to give you more stuff to see and do inside, and releasing a game and a bunch of seperate crap to buy at the same time that doesn't even affect the game much or, worse yet, simply unlocks stuff in the game that was already there in the first place.
Once I graduate with a piece-o-paper in Game & Simulation Design, I'm going to make an MMO with servers here, in Europe and in Korea, where what you buy is a CD to install the game and a small device that accepts your country's currency. You can have anything you want in the game but you have to feed in some money. Want to level up your character's strength? Slip in a five. Want a killer new Broadsword +2? Pop in ten bucks. Want to power-level to the cap? You could just scan in your checking account's number and your next paycheck would be automatically deducted and your character levelled. Clean and beautiful!
I'll be releasing an expansion later that lets you make your character sit down or stand up by pressing a button on the keyboard. It will be 300 BS points, but will also be downloadable for free when I release the second expansion which lets you jump. There are no refunds for this item.
BS points is an online, stored-value system used to purchase make-believe goods with hard-earned money.