This idea will probably stop working when word gets out, but it seems to be working for some people.
If you watch the BTC/USD market on Vircurex, there is usually a pretty big spread, the price swings pretty wildly, and if you can get some fiat over there and place a lowball buy order, there's a good chance it will be at least partially filled:
https://vircurex.com/orders?alt=usd&base=btcAt time of this writing, last vcxUSD is $61, while last mtgoxUSD is $68.90582
Fiat is scarce on Vircurex and is at a premium.
The only deposit method for fiat on Vircurex is VouchX. You can obtain VouchX from AurumXchange or from bitinstant.com. The easiest way is probably from your USD bank account -> Dwolla -> bitinstant -> VouchX USD -> Vircurex, but I'm sure there are more economic ways. I did exactly this a couple of weeks ago and got a great deal.
I'm fiat-scarce at the moment, though, so I thought I'd share for anyone else who wants to try this out. I am assuming that the situation is probably really similar for vcxEUR.