Cages

For most rabbits, all-wire cages are your best option, since they're the easiest to maintain, and typically cheaper than wooden hutches.  The exception is for giants which carry a lot of weight on comparatively small feet.  For giants, it is best to make floors out of planks with gaps between them (think along the lines of the deck on your house).  Some people also recommend plank floors for the more active full-arch breeds like Belgian Hares as well, since they're rather fine-boned and thin-furred.

All-wire cages are usually made with 14 gauge 1"x2" galvanized wire mesh on the sides and top, with 16 gauge 1/2"x1" galvanized wire mesh for the floor, all held together with J-clips and/or C-rings.  I recommend using the wire mesh siding even if you have plank floors.

Solid floors are not recommended because they collect rabbit waste, and quickly develop a thick ammonia odor if they're not emptied out every couple days.  On top of that, you'll risk urine burn even if you provide plenty of clean straw or other bedding (not cedar or pine).

If you decide to go with plank floors, I recommend designing them so that urine drains into the gaps rather than pooling in the middle of each plank (just a tiny, curved slope is all that's needed).  It is also good for the long run if you make it so that the floors can be easily lifted up out of the cage (by people) in case they ever need replacing.  It is no fun tearing a hutch down just to replace one part.

Generally, all cages should be at least 16-18" tall, and I recommend 20-24" tall for giants.  Meat breed bucks (mature at 8 lbs or more) should have cages that are at least 24"x24".  That also goes for single replacement breeders.  The does and litters should have a cage that is 30"x30" or 24"x36", at the very least.  I use both 30"x30" and 30"x36", but when they're triple-stacked such that the top of the stack is at 6', it can be difficult for me to reach the backs of the top and bottom cages with my average human height.  For anyone shorter than that who plans to stack their cages, I recommend keeping the cages to 24" deep.

If you have giants (mature at 12 lbs or more), bucks and replacement should be kept in cages at least 24"x30", although 30"x30" or 24"x36" would be a better recommendation.  Does need at LEAST 30"x36", and I highly recommend cages that are 30"x42" or even 48".  I don't recommend stacking giant cages more than two high unless you (and any helpers) are pretty tall with long arms.

Whether you use hutches or all-wire cages, the rabbits will need to be sheltered from wind, rain, and direct sun.  This means a roof, and solid sides to protect from at least two directions (three is better).  If you decide to put your rabbits in a shed or barn, keep in mind that rabbits are very susceptible to heat stress (it only has to be 80 degrees), and respiratory irritation (ammonia), so it is important that there be proper insulation and air flow.  I usually set up my hutches so that the open side faces north so that they have protection from as much of the summer sun as possible.  If I can't set them up facing north, east is the second choice, since the morning sun is slightly less threatening than evening sun because of the ambient temperatures.  It also helps that the major weather patterns here usually come in from the south or the west.

When cages are set up without stacking, there is no need for something to catch the waste in.  If you set up the hutch in the garden, just rake it out from under the cages to fertilize.  Or, use a shovel.  Some people have also set up a kind of gutter or funnel that directs the waste into buckets that have holes drilled in the bottom to drain any liquid.

If the cages are stacked up, you have to set something up to keep the rabbits in the upper level(s) from peeing on the ones below them.  With two-tier cages, that can be as simple as an angled board between the two levels (usually attached to the front bottom of the upper cage, and resting on the upper back of the lower cage).  Triple-tier cages usually have to be stacked with less space between levels to keep them from being too tall, in which case, the only option is to use trays.  Trays need to be dumped at least once a week, if not more.  I usually find that a tray under a litter will have to be dumped every 2 to 3 days.