I just want to share this experience, as many have been curious about this in different threads: I exchanged my custom HDD in my 17 classic MBP for a 1TB WD Scorpio Blue, and everything runs perfect: I have plenty of space at last ( and three comfortably sized partitions!) and disk performance has also improved a lot according to geekbench. The disc is 12.5 mm in height, but fits in well. (It should also fit in every alu-unibody with exchangeable battery) Anyone still thinking about upgrading internal disc space: Go for it! The exactly described steps to put it in I followed from ifixit.com.