All power boards sold in Australia must have overload protection built in. Perhaps some grey imports or older boards do not, in which instance they should not be used.
The majority of power boards are rated for a total AC load of 10A, equivalent to 2.4kW (2400W). This is more than adequate for most small household appliances. High powered loads such as a column heater, toaster, kettle, electrical cooking appliances are better plugged directly into a wall socket. Having more than one on a power board is likely to overload the board.
Modern TVs, PVR, NBN modems, phone chargers etc only draw low levels of power. From perhaps 10W for an iPad charger up to 200-300W for a modern LED TV. All devices will have a nameplate with the rated power in Watts and maximum AC current in Amps.
It’s always worth getting a power board with a few extra outlets just in case you need a spare later on. The extra cost is minimal. The better quality power boards have some of the outlets further apart. This helps with larger plug packs that often block access to the adjacent outlets. It is also worth looking for a power board with a power switch if the wall socket it is to connect to is hard to access. As per @grahroll the extra expense of a surge protected power board is likely a good investment. In particular if you connect to a long rural feeder where lightning strikes or tree falls are a high risk.
