Machine 1 (desktop):
1 x 240GB SSD for me OS, programs, and a few games
2 x 1TB HDD in RAID-1 for documents, data storage, etc.
1 x 1TB HDD for me page file and the rest of me games
so...that one has 4
Machine 2 (media server / HTPC):
1 x 180GB SSD for me OS and programs
1 x 1TB HDD for page file, timeshift buffer, documents, and games
4 x 2TB HDD in RAID-10 for lots of data and media storage
so...that one has 6
Machine 3 (media client / HTPC):
1 x 120GB SSD for OS and programs
1 x 320GB HDD for page file, timeshift buffer, and documents
just 2 in that one
Machine 4 (notebook):
1 x 500GB HDD for everything