Like if an Amiga had a gabillion transistors...

I just picked up Prince of Persia: Sands of Time, and I have to say it is definitely game of 2003. I picked up Call of Duty at around the same time (last week) and finished that (it's not that long) but the quality makes it well worth it.
I'm a bit of a sucker for your very immersive, well thought out themed shooters, and CoD is the best so far. The engine is fairly aged (well, the Q3 engine is fairly old now, and there are people who have licensed the Doom3 one already) and the AI is not the finest (though I can think of few games that do better than it) but they overcome these things so well.
Some of the set pieces are stunning, and though it is true that the impact of the hundreds of men firing at you and with you fades after your first run through, it stands up well to replay, since the difficulties change it noticably and you have to really think about how you do things, organising with the team and such.
But anyway, PoP - stunning game. The graphics are beautiful, gameplay is stunning, and the puzzles are both well designed and true to PoP's roots. The animation is superb as well; you can run along a wall, miss the thing you were aiming for, slide down the wall, jump from it, grab something else and pull yourself up all in one stunningly smooth run, no jumping between animation cycles.
The gameplay truly is wonderful. The fighting, with many possible moves, on few keys being completely attainable. No button bashing and it's so very fast.
Good news with PoP is that despite the quality of it, I have played about 6 hours maybe and I am only at 33%. And I don't see me getting bored with it.
Also, the sand stuff is done nicely - you can slow down time, freeze an enemy, or freeze all the enemies. You then have the option to rewind if you screw up, the number of times, depending on how many sand tanks you have filled (the number increases as you find more sand whirly things). You also get visions of the future - small hints as to how to solve puzzles, at your save points, which are many, thankfully.
Even the camera, which in third person could be a nightmare, is done well. It is easily controlled, and you get the option of a level view - which zooms out to give you betetr views of what you have to do, or first person which lets you look over ledges in certain areas to check things out.
Basically, it's a stunning game. Now I just need some more new games for when this gets finished!