Certain conversions such as police stations and former pubs make great homes. They are usually well set in a town or village and are often Victorian so are well built. One of the downsides is that they can have very limited land around them so creating a garden might mean digging up a car park, which is not for the faint hearted.
If you are buying a pub which you are converting you will need to consider change of use so must take advice and know what you are getting into. There is a lot of feeling in rural communities about pubs; many people feel they shouldn't be sold off so you might make yourself unpopular with the locals. However, if the business is not a viable one, they can't really complain.
Church and chapel conversions are slightly more difficult as they are more of an acquired taste. Some people get spooked about living in a church and the grounds often have graves which can't be moved. The other issue is you tend to get one huge room so it can be difficult creating a domestic space, particularly for a family. The cost of converting buildings like that can also be prohibitive.
One thing to consider is if the building is in a poor state of repair that you may struggle to get funding, which will mean doing the work, paying for it yourself and then getting a mortgage retrospectively.
One of the best conversions I saw was a Georgian chapel of rest in Wiltshire. It was a beautiful building with lots of marble memorial tables on the walls - not to everyone's taste but it was listed so they had to stay. It was richly decorated, almost Gothic in feel, but it's good to be aware that selling on a wacky property can be tricky because of the limited resale market.