If you use your machine for development and plan on buying new hardware fairly regularly then the figures add up to a no brainer. Particularly this year with Leopard coming out.
If however you don't plan on taking advantage of some of the other benefits then it's a harder choice. Particularly if the projects you work on are non revenue generating (open source for instance). I think one way for someone like Richard to go would be to have a donations link for the software he has available with the simple statement that if people want advance notification of whether the code works on pre-release versions of OSX then enough funds would need to be raised to make it happen.
Simple fact is though that's a personal choice and obviously not everyone is going to want to even consider going down that route
Only 2 days, 6 hours and 30 minutes to go now though!