As per the thread title, I'm veering towards arriving at a decision to buy some bitcoin.  It may be a modest some to most but it's substantial for me.

Which exchange is likely to offer the best rates?  Should I register with a couple?

How do I protect myself from the dangers of using an exchange? i.e. I know not to use a wallet provided by an exchange.  However, should I buy in increments - so that I don't have a lot of FIAT on account at a given time (just in case I'm unlucky enough to get caught at that particular moment with the exchange collapsing)?