Joe: Call of Duty 4’s map pack gives you four new maps for 800 points. Halo 3’s DLC gives you three maps for the same price, but two of them are half-assed remakes of maps you’ve already played! Don’t even bother trying to call it “fan service,” it’s more like “fan abuse.” I reckon the two remakes count as half a new map, so you’re really only getting one and a half maps compared to four for Duty. The value proposition is clear: Call of Duty 4 is giving you new content for your money, while Halo 3 is just looking to squeeze more cash out of you.
Charlie: I can fudge math, too, you know. Let's see... Halo 3's Legendary pack offers three new maps. Avalanche, though, is easily large and diverse enough to count as two maps, so that brings the total up to four. Call of Duty 4's Variety pack claims to offer four new arenas, but Killhouse is barely half a map, so the real tally is more like three and a half.
There you have it. Four is clearly greater than three and a half. Halo wins!
(Plus, if Halo 3's past downloadable content is any indication, the Legendary maps will be available for free in mere months. Your move, Duty.)
Joe: As mentioned in my “Value” rant, two of Halo 3’s three new maps are remakes of maps from Halo and Halo 2. Blackout is Lockdown, and Avalanche is Sidewinder. Just toss in a Bubble Shield and charge 800 points: the suckers will buy anything! The coloration filters might be a nice touch for machinima makers, but they’re really nothing more than the silly cheats you get when you collect Intel pieces in Duty’s single-player campaign. So that’s not even very original, and doesn’t add anything substantial to gameplay.
Sure, Chinatown is based on Call of Duty 2’s Carentan, but Infinity Ward has transplanted it from 1940s France to modern-day San Francisco. Plus, the ambience and flow of gameplay is totally different because the game has evolved over time. Unlike Halo, which has barely changed through two sequels, so its stale knockoff maps play nearly identically to their predecessors.
Charlie: What Bungie has done with Blackout and Avalanche, the remakes of Lockdown (Halo 2) and Sidewinder (Halo), is most definitely fan "service," not "abuse." Experiencing these maps for a second time is like reuniting with an old and familiar friend... if that friend had won the lottery, got an expensive facelift and bought a whole mansion of cool new toys since the last time you saw each other. The designers have carefully recreated what you loved about the originals, while also fixing flaws, throwing in surprises and supersizing the entire damn thing to Halo 3 proportions. These are not lazy and lukewarm leftovers.
In addition, I'd argue that Ghost Town is far more original than anything in Call of Duty 4's set. You've already described it as Gears-like. I've also heard comparisons to Counter-Strike and - what do you know - the mighty Call of Duty itself. Ghost Town is a strange and wonderful anomaly in the Halo 3 universe. Call of Duty 4's Chinatown, Creek, Killhouse and Broadcast may look different than their predecessors, but they play like more of the same.