Your choice of technology is very important it can completely change the use of the space. For example if you go for 30 desktop computers you are very fixed in the style of learning that will happen in the space.
The amount of space you have available may limit your choices. I believe that a combination of technologies is the best way to use your space. It is great for students to be able to work together around a desktop computer, work alone, take a laptop to another area or even just relax in a comfy chair with a tablet computer.
In order to encourage collaboration around a desktop computer you must give space for this. Either give big space between each computer or use specialist desks to help you achieve this. There are some good curved desks available which allow more students to work around one computer.
Laptops and Tablets are very successful in a modern learning space because they lend themselves well to being used just about anywhere in your space. Students can easily turn it, pass it and move it to really get the best use. Charging can be an issue but there are many laptops available these days that will last a whole day on the battery and tablets even longer, allowing you to charge them in a charge station overnight.