In short, there are two main stylistic camps; tactical and adrenaline.
Adrenalin design is much like it sounds, almost the candy of video games. Lone wolf, run-and-gun styles that make very little sense outside of that game world, or even in it, but are a cheap hook to get lots of players. Call of Duty, in recent years, has been a great example of this philosophy. This sort of design is often pursued by large, established studios where executive meddling is more rampant. However, some games, such as Halo, use the magazine limit as a sort of damper on weapon effectiveness for balance. Because they consider magazines very similarly to cool-down or spin-up, they don't use them as units of ammo like in the real world. There's some merit to that discussion. (For example, in Halo Combat Evolved, most human guns were good for 4 kills per magazine if every shot hit. This let them focus each weapon on role rather than a hierarchy.)
In tactical design, teamwork, tradeoffs, and thinking as you play are vaunted, but you lose some of the addictive adrenaline. This allows clever players who aren't necessarily as "twitchy" to stand on a level field with their hair-trigger foes. This sort of design is often more popular with smaller studios who can make non-mainstream calls like that. A great example is Frontlines: Fuel of War, where the assault rifle loadout got about a dozen magazines and half dozen launcher grenades. The result was that you could always be prepared for a shootout and and that some waste was acceptable, but 1-round mags were totally averted.
The conclusion is that you should use whatever fits your overarching vision for the game. Will it be more tactical? Give them lots of ammo, tie ammo to mags, and let them sort it out! Will it be more adrenalin-y? Don't make them think too hard!