I know it's probably been posted and talked about a lot, but in the current climate (and I know that the future cannot be predicted) fixed or variable. I can make the payments without too much hardship, and don't intend to move for the forseeable future.
It has been posted and talked about a lot already so please check out existing threads.
If you are comfortable with your mortgage and can even afford to make additional repayments then you should stick with the most competitive tracker rate on offer for your circumstances and forget about fixed rates.