DNA quantitation question

[G.]

This may be quite a basic question, but it has been troubliong me for
some time.
I am currently working on a project using PCR to quantitate mutations.
Quantitative PCR has it's own pitfalls, but my question is more
fundamental. I extract DNA from mammalian tissues, using a high salt 
protocol and I use a spectrophotometer to calculate my DNA concentration.
I have found that this can be quite unreliable. If your DNA is quite 
concentrated, then pippeting it is extremely difficult. Resuspending 
your pellet in a large volume helps this, but even then if you repeat it
you often get different values. My question is, is there an established 
method for calculating DNA concentation, which is more accurate than 
using a spec.
Your thoughts on this would be appreciated
Gareth Jenkins