it depends pretty much on where you live.

good exchange for depositing EUR or USD fiat are:

- coinbase https://bitcoincashback.net/coinbase-review.html
- bitstamp
- bitfinex (currently under SEC Investigation, min 10k USD deposit to trade) https://bitcoincashback.net/bitfinex-review.html
- bitcoin.de
- kraken

I linked my reviews to two of the sites I listed.