A central heating bathroom radiator will work off your central heating system and typically work out cheaper than the electric equivalent. If you have a larger bathroom then you will find that having a radiator in place of a towel rail to be a better choice. This is because the radiator will heat up the bathroom quicker than a towel rail can.
There is also the option to have a towel rail attachment on the radiator allowing you to dry your towels on it too. They are available in a large range of colours available and models that are moderns and also traditional models too.