Getting the right bowl and seat for your bathroom is not a complicated process. There are a few key points you will need to know going in, but once you have these down you should be able to choose one with confidence.
Floor mounted and wall mounted toilets
Before you decide on a toilet bowl, you will first need to decide whether it is going to be floor mounted, floor mounted with a wall outlet or wall mounted. These refer to what the toilet bowl attaches to (i.e. to the wall or floor), and where the drainage goes.
The type you’ll be able to choose will depend on any existing plumbing, and where the waste pipe feeding to the sewer is positioned. If it is in the floor, then you will only be able to choose the floor mounted variety, but if the pipe is through the wall, you will either need a partially or fully wall mounted toilet. To ensure that you’re choosing the right floor mounted toilet, you will need to know the distance between the centre of the waste pipe and the wall too.
Wall mounted toilets, because they not only need to bear their own weight but the weight of whoever's sitting on them, will need additional reinforcement to be installed in the wall to sustain the extra weight. While installation of wall mounted toilets is a fair bit more complicated as a result, they can look quite stylish and allow you to clean the floor under the bowl.
Round or oval-shaped toilet bowls
The next thing to decide is whether you want a rounded or elongated (oval) shaped bowl. Rounded bowls are shorter, which is useful in smaller bathrooms where space is at a premium. Likewise, most toilet seats are manufactured to fit rounded bowls so you will have a much wider selection to choose from. An elongated bowl is more comfortable to sit on though, and if you have the room they're a comfortable choice.
One piece and two piece toilets
Toilets come in either a one or two piece configuration. The two piece type has the cistern manufactured separately to the bowl, while a one piece toilet seamlessly integrates both the bowl and the cistern as a single unit. There is no real practical advantage to either type, but the one piece looks more stylish and is a little easier to clean. One piece toilets are usually more expensive.
Almost all toilet bowls are made of porcelain. While stainless steel models do exist, they are generally used in larger institutions such as prisons and schools. Stainless steel toilet bowls are stronger and won't crack or chip, but are rarely used in homes.
Porcelain toilets are available in many different colours too, but anything other than classic white tends to cost a bit more as it requires a special glazing on the porcelain. For those who are looking for a true throne, there are some very ornate bowls with engravings and Victorian features cast into the ceramic, and even some gold-plated models. If you really want to spend some money, there are even models available in Japan which can collect all sorts of information about you when you use them, and email the results to your doctor!