Identifying Hard Drive as performance bottleneck for desktop machines

I'm working in a development team where we all use laptops so we can work in multiple locations. These laptops are proving notoriously slow for development work, but at a glance they all look to have the specification for a much faster experience:

• CPU – Intel Core 2 Duo T7500
• Memory – 2GB of RAM

We all experience the biggest delays when the hard-drives are being accessed, particularly when swap-files are being thrashed. After doing a little bit of profile, a colleague discovered that our HDDs are seeing Read/Write speeds of about 10MB/sec. This seems abnormally low and we believe it the cause of the problem.

Sensibly (though somewhat annoyingly) our business wont blow money on faster drives just to see if it fixes the problem; we need to illustrate this is definitely the problem and that buying some solid-state drives will make it go away.

I need some way of showing how 90% of the system resources aren't being used over the course of a day, and that whenever there is utilization, it's all in HDD reads or writes. Are there any tools I could use to provide this information?

Does it seem likely the problem is going to be fixed by a faster drive? Should I be looking for alternatives?