It would be more encouraging if the point system was somehow weighed more by the proccessing power of the device actually performing the task.
Not to say that slower CPUs should be penalized for taking 50-100hours to complete 1 WU, but systems being able to complete multiple results in 1 day should be considered to recieve 'extra' points.
This would reward users with somewhat more power machines at their dispossal and encourage more people with such systems to devote some time to the project.
As an example, I've got a few machines running the grid atm. My faster machines being 3.2ghz+ are cranking out 3-8 results a day, yet recieve very little points for each result. Where as my slowest machine being only a 550mhz P3 is rewarded thousands of points for a single WU because it took over 2 days to complete.
Although yes, if I had my higher end devices cranking away 24/7 on just the WCG they would in 2 days earn just as many if not slightly more, but they would of sent 600%-1600% more results back...
Not asking to weigh every single device and make a basis of what score they get per result and CPU hours themselves, but if the client software is able to 'rate' your machine against the 'highend desktop' being a 1.5ghz P4. Then surely that score could somehow play into being the basis for a multiplier on your points earned for a WU.

So the baseline is '100', if your system is rated by the client as being 200+ why not be getting a 2.xx multiplier? 156 gets 1.56 multipler etc.
Though a machine rated below 100 should still just get the 'standard' 1x points for their CPU time.

And yes I have noticed that the client application's rating of your device does differ, and this I have assumed is dependant on just how many other proccesses you have going on. When using one of my higher end machines for work and play I notice my 'rating' falls to ~198 but when it's been sitting all night and basically the only thing working is the WCG client it rates my machine at 209. So really this could be even more of an advantage to the weighed points. 'Dedicating the night to just WCG? Here have a bonus!'

Otherwise, if points were someones goal. It would be better to run a dozen very slow machines that only splurt out a single WU every few days than bother running it on any of your workhorses let alone anything that's actually built to do these kinds of calculations very quickly.