Radiant Dawn on Wii is my favorite (followed by Path of Radiance). It has the best battle themes out of all the localized games--and in great number--and some maps are just insane with the number of units, which really helps drive the "we're at war" aspect of the game.
Normally I'm not entirely fond of tons of units on a map, but in Radiant Dawn it feels right because it's usually for big moments.
Something else I enjoyed was the structure Radiant Dawn's story presented. You control both sides of the conflict, and seeing each side's view of the opposition was really intriguing, because you'll probably grow fond of characters from every side and feel conflicted about who you're rooting for. And, coming from Path of Radiance (which is the first of the duology), it's interesting to see where your old teammates wound up. It's an effective storytelling method that worked on me, but people always complain about the first group you control because they're not the Greil Mercenaries from the first game.
Awakening is a great starting point for people new to Fire Emblem, but it just doesn't reach some of the highs the older entries have set. When it tries to, it still doesn't quite stack up... but new players won't have anything to compare it to, so I guess it doesn't matter. Overall, I was extremely hyped for Awakening (I even bought a 3DS for it), but it just didn't have the same magic the prior entries had. The team-up mechanic was great, though; but I can live without it and play Path of Radiance and Radiant Dawn just fine and not miss it.
Chrom from Awakening is such a boring main character, too. I'd probably have more fun fisting myself with sandpaper and pouring alcohol afterward than reading his dull personality via the great localization. He's probably only popular because he can make BABIES with (almost) ALL THE WOMEN, and not because he's a good character.
Ike, though? Yeah. That's a fucking great character right there (you'll have to play Path of Radiance to see why, though). Badass motherfucker as the game goes on. Some of the lines he has against bosses make him even more awesome in my eyes. Some examples:
Ike: Are you the commander of this battalion? Order your men to retreat, and I'll let you escape with your life.
Boss: Don't push your luck, mercenary dog!!
Boss: I will not allow you to take one step more!
Ike: Then I've no choice but to cut you down and walk over you!
Boss: You fool... What are you doing on the front line? This is no place for an officer! If you die, your army loses. Soldiers fight; officers lead. That is the foundation of war!
Ike: Hate to tell you this, but I'm not an officer, and I'm not in the military. I fight with my men, and I bleed with my men. I lead the Greil Mercenaries. If I can't fight, I've no right to lead.
Boss: Bah! This is war, not some child's game! The only thing that matters here is who fights and who dies.
Boss: So, you are the new commander... Tell me, boy, what cowardly tactics did you employ to fell our brothers? You must have deceived them. There's no way rabble like you could defeat Daein troops in a fair fight.
Ike: From the very beginning, every last one of you has underestimated us. Will you never learn? Your refusal to recognize our strength will forever keep victory at arm's length.
Boss: Silence! Silence, you idiot child!
Ike: You're right. No more talk.
Ike <3
Of course, Radiant Dawn does have its flaws: mainly its stock support conversations instead of unique ones per units. That's really the biggest one, but you learn to accept it.