32 GB is a good beginning, but when you find out that you could stream video/music to your tablet/laptop, maybe you'll need more. The idea is that let Pi download things 7/24, and when it's done, stream things to tablet/laptop to watch. So you don't need to move things into your tablet/laptop.
And I only tried Raspbian, you can use "sudo apt-get install transmission-daemon", or get source from
http://www.transmissionbt.com/ then "./configure; make; sudo make install".
Transmission pre-installed OS also exists:
http://www.raspberrypi.org/forums/viewt ... 3&t=100976