OK, so from Mt.Gox USD to BTC-e

aurumXchange charge 4.00%
BitInstant charge 3.99%

Some quick calculations for reference

110 - 105.60
120 - 115.20
130 - 124.80
140 - 134.40
150 - 144.00

I've noticed there doesn't seem to be as large a gap between Mt.Gox and BTC-e of late, so unless the fees come down there is now little use in this service.