In my solo league,
Barry Bonds hit 610 HRs, playing from 1986 to 2003. He did have two of the best seasons ever, going .372 with 65 HR and 148 RBI in '87 and .396 with 68 HR and 176 RBI.
The all-time leader for a season is Mark McGwire, who actually has the top two seasons of 72 in '87 and 69 in '96. The 2 years mentioned above from Bonds were #3 and #4.
The career leader is Ken Griffey Jr, who is still active at the age of 40 in 2010. He has 840 HR, 165 more than 2nd place Alex Rodriguez, who is also active as of the last sim.