A lot depends on the size of the rabbit, if it will be indoors or outdoors and how much time out of the cage it will get. A dwarf breed living inside with lots of out of cage time can get away with a smaller cage than one that doesn't get as much out of cage time. The cage size can be limited by the space you have and your budget.
The general rule is the rabbit should be able to take 3 full hops from one end to the other. It should also be able to lay down and stretch out in all directions and be able to stand up without touching the top. There also needs to be space for a litter box (if you use one), a nest box (if you plan on breeding and have a female), food and water containers, toys, and a place to hide.
I would go no smaller than 2X4 ft. If you have the space for a larger cage, go for it. For an English Spot, a shelf or level would be good so it can jump up. A shelf is good for most rabbits if you can give them one.
For a mini or holland lop, I would still go for a larger cage. Again, a shelf is a good idea.
A large or giant wire dog crate will work. An x-pen can also work.