Well, color me somewhat impressed. I had written this game off simply because Infinity Ward had nothing to do with it. Treyarch (the Spider-Man games and Call of Duty: Big Red One) took the helm for this iteration as IW works on Call of Duty 4 for PC only (supposedly).
Call of Duty 3 seems to borrow a lot from the previous game. You are put in a variety of roles for different countries on the Allied side. Instead of only controlling one soldier, you control the path of many. Also much like the last game, Call of Duty 3 is a very scripted game in the single-player universe. I personally don't mind it, but I know many people that don't enjoy playing these World War II games that have you go from point to point and never have an adaptive AI that comes at you all the time and not at intervals. I'm sorry to tell them that many FPS and 3rd person action games are scripted and checkpoint based, it just depends if you've grown tired of these crutches or not.
The graphics and sounds in this game are top notch, but there have been some missteps here and there that I have seen. Your friendly AI troops seem to enjoy getting in the way of gunfire and sometimes they just disappear from sight. Add to this the fact that the enemy AI sometimes starts to shoot like characters in GI Joe (not being able to hit the broadside of a barn) and miss you at point blank range.
The controls are pretty nice, but I would still love to have mouse and keyboard controls. I think I'm pretty hardcoded with the whole FPS control issue. If a game starts off in the PC world I have a hard time adapting to console controls. I just don't feel I have the pinpoint accuracy I have on the PC. On the reverse side I find that if a game starts off in the console world (Halo for example) I find that the controls are nice and tight and find my accuracy to be very good. I don't know if that means there is a different conceptualization of the controls depending upon where a game starts off, but it is interesting to note. In the case of Call of Duty 3, even though it isn't coming out on PC it is obvious that it has been built upon the last iteration and that game started off as a PC game even though many would consider the 360 version better from a graphics and sound standpoint.
Call of Duty 3 takes place during the Normandy Breakout Campaign period, meaning it takes place after the landing and follows the allies as they try to take back sections where the Germans held ground. This means you won't be re-living the Battle of Normandy in this game, but there are plenty of "Holy shit!" moments in the game thanks to the terrific sounds in the game. As I said in my opening statement, I am somewhat impressed by this game on the single-player side simply because I figured Teryarch would drop the ball. In the end they've kept the ball rolling, although it certainly isn't as engaging as the last game honestly.
Where Call of Duty 3 really shines is in the online world. This shouldn't be a surprise given how popular the last game was online for the 360. I've played a few games (Capture the Flag for the most part) and I find it quite fun to play. The voice communicator runs nicely and I can hear everyone. The only negative I have seen so far is there hasn't been any ranked games that I've been able to get into, only unranked ones. This is fine since I could care less if I'm on a leaderboard or not, but I am surprised more people aren't playing ranked games. They could of course all be playing Gears of War, but I figure this game will be quite popular as well.
In the end I'm leaning toward the Buy It category simply because of the online gameplay. If you are leaning on it strictly for single-player play I would rent it because you should be able to finish it within the rental time. $60 for a multiplayer game may seem a bit steep, but the fact is you can get more people in one game playing Call of Duty 3 than you can get in Gears of War. The more people, the more fun it is honestly.