zfs discuss - Jan 2010 - Trends in pool configuration

My main server doubles as a both a development system and web server for 
my work and a media server for home.  When I built it in the early days 
of ZFS, drive prices were about four times current (500GB were the 
beading edge) and affordable SSDs were a way off so I opted for a stripe 
of 4 2way 320GB mirrors.  This gave me good small read/write performance 
for compilation and enough capacity for media. 

Now I''m looking at replacing the box something quieter and cooler. 
With
the improvements in ZFS and media, I''m looking at splitting the pool: 
A
mirror of 2TB drives for media and a mirror of SSDs for build workspaces.

Which leads to my question:  Are people splitting pools based or 
workload, or opting for a single pool and cache devices?

-- 
Ian.