I think the interval is 190,000km or 10 years, so you are overdue.
I bought a kit from fcpeuro.com with a Continental belt and INA pulleys and tensioner. It was cheaper than the local Gates, etc on offer and arrived in less than two weeks and should be much better quality as they are the OE suppliers I believe.
From my research, Volvo recommend a water pump replacement every second belt change and water pump failures are rare and the only issues I heard about were leaks. So if you want to be cheap (like me) you could skip the water pump.
You should change the other auxillary belts if they haven't already been done as if they fail they can take out the timing belt.
As others have said, coolant expansion tank is a common failure item and you could change one of the radiator hoses (the complex and expensive one) if you are going all out on preventative maintenance.
The top engine mount has to come out to replace the belt and these tend to last a short time so you might consider that too.