Depends on where you want the speed, and where you do most of your work.
For example, on my work laptop (and home PC), I do very little work at the host OS layer, so leaving the Host OS on regular HD makes sense for me, and leave my VMs on the SSD(s) for performance.
For desktop at home, with recent sales, I got a 60GB SSD and I plan to move OS system/boot onto that SSD, leaving most of my VMs on an OCZ Vertex 2 120GB. The WD Black 1TB drive that came with the system does well enough compare to my older WD Raptor 10k 150GB, that lower priority / I/O need VMs will move onto that (removing the Raptor drive to reduce power/heat).
On a laptop,
- if you are using a physical drive, contain your host OS and VMs, you have spindle contention. Move onto a SSD, and you no longer have spindle contention (though depending on usage patterns (unlikely, but possible) might have bandwidth limitations).
So for your laptop - what are you looking for?
- want the Host OS to boot quick - then you want to keep that on SSD
- The VM will be slower moving it back onto a physical HD vs the SSD
Depending on size of your Host OS footprint, you might want to keep the OS and VM on the SSd, and install larger (less frequently used) apps and data files to the physical HD.
- becuase of my usage pattern, I like keeping my VMs on the SSD, and not worry about the host. I also picked up a couple of cables ($10-15) that allow me to run the SSDs as external drives off the laptop (without enclosure. eSATAp on Dell's a combined eSATA - seperate USB with one SATA connector on other end for HP/other with eSATA (but not powered) port)
- Have you become spoiled with SSD speed and want space and speed for Host OS, and spped for VM? maybe get another SSD (instead of re-using hte 320GB SATA HD for the drive carrier? You could keep the 320GB for storage/backups
