If you take the probabilites multiple by the electoral votes one gets:
Expected Bush Electoral Votes: 284
Expected Kerry Elec Votes: 254
This is analgous to saying if I flip a coin and win $10000 if heads or $0 if tails then the expected value of the gamble is:
50%*$10000 + 50%*$0 = $5000
Yes, but what matters is not the "expected" number of electoral votes, but rather the probability of winning a majority of the electoral votes.
Consider the following scenario: