I bought my first BTC on Coinbase with a straight-up bank transfer. I opened an account on Bitstamp at the same time to compare, but went with Coinbase because they're based in the U.S. The significance is that I didn't have to provide photo ID to get verified. Also, I thought if there was a dispute, I might have better chances of resolving it with a U.S. company than a foreign one. I might buy my next BTC from Bitstamp, which is based in the U.K., if there is some advantage to buying BTC there.
I opened another account at my bank to use for transfers with BTC exchanges, and transfer money between the two. That way if the account is somehow compromised (user/pass hacked), my paycheck and rent money are safe. I check both Coinbase and my bank account every 1-2 days to make sure everything is the way it should be.
Now that I've got a little experience at buying, I'm looking at selling to those who can't or won't do the bank transfer process. It looks like there's a market out there for that, from what I've seen on sites like localbitcoins.