Space saving desktops

Hi

I am looking out to buy a desktop which saves on space
Yes I would like to assemble one but owing to space constraints and the dust which accumulates, would like to keep it simpe
The typical options which come to my mind are

1. all in one desktops (non touch)
2. Mac mini
3. other non mac minis if available
4. are there slim desktop assembly options

Typical usage-Home--surfing, youtube, movies casual gaming

Could anyone suggest are the above options woth it
Budget not over 35000/- INR

Thanks
Ninad