The Los Angeles Dodgers
Who has the best ERA for a MLB season
2001 Seattle Mariners they went 116-46.
The Chicago Cubs at the moment (6-6-08)
51
In the 2009 season, Mark Reynolds struckout 223 times which was an new MLB record. He broke the old record of 204 set by ... Mark Reynolds in 2008 season. He is the only player in MLB history to have struckout 200+ times in a season.
1 and a lot
The New York Yankee's
it is tied between the seattle mariners and the Chicago cubs.
Through the 2009 season, the record for a season is 4,483,350 by the 1993 Colorado Rockies.
Barry Bonds
The St. Louis Cardinals had the best regular season record in 2005, going 100-62. http://mlb.mlb.com/mlb/standings/index.jsp?ymd=20051002 (full standings for 2005)