I have a long history with "silent" PC's and so am interested in making TiVo as quiet as possible. (Given the original's are 5400rpm, performance is not really an issue here so noise is the big one for me).

My view...
Original 20G (and aftermarket 80G) Maxtors sound like a helicopter.
I ordered and sent back a WesternDigital 200G as it was better, but still noticably loud.
Will be using a 120G Seagate Baracudda IV from my old (silent) server and replacing it with a new Seagate 200G 7200.7 (~$220).

So, for me Segate is the right choice... (Samsung also make a really quiet drive).

Heatwise, the slow turning stock TiVo fan is very quiet and easily keeps it's cool.

What you got and why? How's it for noise?