After reading this thread yesterday, I went home last night and tried just what Ari described: Tiny map, 3 other Civs, with me as the Persians. And I gotta say, his strategy worked exactly as he described. Iron cropped up right on schedule, and my Immortals (combined with Knights a little later on) went through the opposing forces like butter. In succession, I eliminated the Americans, the Germans, and the Japanese and scored a Conquest victory in the mid 1400's.
Is it a limited strategy? Certainly. My one stab at it revealed that even on a Tiny world, wars of aggression are tough to sustain; the amount of troop movement necessary is burdensome, and it's a delicate balancing act to make sure you're hitting the right place at the right time. And even in a game where my sole purpose was supposed to be to find other cultures and kill them, I still found myself building Wonders and sending out settlers, just for the sake of variety! I don't think I could play a solely military game of Civ (besides, I have Starcraft for that!

)
Still, I admit that it was a nasty thrill to be an unabashed warmonger, especially when I got to watch my Army unit (3 Immortals) take three enemy cities in as many turns...
This little experiment revealed something else: In case you weren't sure, the scoring system definitely doesn't reward purely peaceful development! Through most of the game, my score was in the high 80's to low 90's, with the other Civs somewhere in the 50's. Once the game awarded me my Conquest vic, though, it showed my final score as being almost 900 points! If I'd simply blockaded the last Japanese city to prevent growth or escape, and then concentrated on building culture, science, and settling open territory, I wonder how much higher the score might have been.
I don't think I'll play many games this way, but it was an interesting change of pace!