Efficient backup of virtual machines

I'm currently experimenting with backing up WinXP virtual machines from VMWare fusion.

I don't want to be backing up temporary information which is continually changing so I'm looking at the following solution:

Use a filter to prevent backup of:

vmss - the temporary vmware system state (for me about 130Mb)
vmem - the snapshot of system memory (for me 768Mb)
log files - small but non essential

Secondly inside the vm I create a separate virtual disk and then put the WinXP pagefile in this disk. I can then exclude this disk from the backup (another 768Mb of saving).

Initial tests seem to indicate that this is a viable and efficient solution.

To restore a VM you just need to recreate the pagefile virtual disk and all seems OK.

Any thoughts on this as a solution?