Gotta give props where props are due and they are due here. Frank Robinson is criticized as a bad manager (he hit the pitcher 8th last year or something like that, among other things), but it appears like he's doing a good job of keeping the team loose yet focused. Plus, the move to DC has helped the team, since they actually have a home crowd cheering them on now. Back in Montreal, nobody showed up. In San Juan, they just cheered their native Puerto Ricans, regardless of team. Sometimes you call a player a "ballplayer," because he is one of those guys who doesn't wow you with flashy speed or tape measure shots, but just fits in the game. The Nats are full of ballplayers, as well as underrated players. Jose Guillen was labeled a cancer, but has grown up (much like Milton) and is quietly leading the team on the field. Nick Johnson has stayed healthy and as dubbed by Rotoworld, is the "OBP Jesus." Castilla is the senior leader on the team and is bringing veteran leadership to the team. The staff has been quietly pitching well, led by Livan Hernandez. Chad Cordero has been a top closer thus far this season. Everything is clicking for the Nats. AND, Jose Vidro has been out for quite a bit.
That being said, I do not see it continuing, especially in that division, where Florida hasn't even heated up yet. Sure, the team is hitting well, but I don't see the offense as being much above average. The pitchers are pitching way above their heads in my opinion. Jim Bowden made some questionable signings in the offseason (even though I don't see the Spivey trade as being bad...I don't trust Ohka anyway and Drese isn't much worse, albeit more expensive). They'll eventually get lost in the shuffle, but I think what they've shown has been great for the game.
About the strength of the divisions, the NL East has been the best so far this season. ALL of the teams have records above .500 and the only sub .500 records of any teams against any other division are the Nats vs. the Central (6-7) and the Braves vs. the West (3-6). Incredibly, all the teams are above .500 when they've each played approximately 30 games against each other. That means that the NL East teams are representing and beating the teams of other divisions.
(sorry, misread your post...I thought you said it was the strongest this year, which is ludicrous) NL Central is not the strongest division. First, there's obviously no parity here like in the NL East and the first place team only has a three game edge on the Nats. STL is running away with it. CHC is hanging in there, Pittsburgh is making a run but still at .500, but then you have three sub-.500 teams in the division. That does not cut it.
If not for the weak link of Tampa Bay, the AL East is a very strong division. The Yanks will get back in the hunt soon enough, Baltimore has been superb, and the defending champs are playing well, too. Toronto has been a Natslike club this year, getting it done without many stars. Without considering Tampa Bay, I think this is the strongest division. However, it is much more top-heavy than the NL East, which has plenty of parity. I think the best teams of the AL East are better than the best teams of the NL East, but the bottom feeders of the NL East are not really bottom feeders at all, but competitors, while Tampa is horrific and Toronto is questionable in the AL East.