You don't have to go for all-fixed or all-variable: you can typically split your loan and fix part of it. This effectively lets you hedge against the interest rate risk - you aren't as exposed to rising interest rates, but also don't benefit as much from falling rates.

The main downside of fixed loans is that you usually can't reduce your interest payments by making additional repayments (because ultimately they are backed by long-term bonds issued by the bank).