For years now I have been running Prime95 on some of my computers. (I'm 256 on the top producers list right now). But I've decided to try branching out. I know SETI@home is one of the older projects and I decided to give it a try. I'm only a few days into it and I only have about 7,000 credits on my account. It is cool that SETI@home has a client application that is able to use the GPU. So on my quad core system, I can have 5 concurrent tasks (1 GPC, and 4 CPU).
Distributed computing has always seemed very interesting to me as a software developer. Unfortunately there are only certain projects and applications that lend themselves to this kind of architecture. Most applications are tightly coupled and even if they can be "distributed", it's likely that the best you'll get is multiple CPU's on the same host computer. Some tasks can be distributed across multiple computers that are co-located and/or have high speed interconnects like most super computers these days. But even many of these tasks require that the systems are the same hardware/OS/etc, and thinking back to my college class on parallel processing, they can be hard to write well (so they run efficiently and correctly). There really are relatively few projects that fit this mold of being able to be widely distributed across different machines that only communicate on an infrequent basis. But it is a really cool concept, that seems to be gaining more traction in the commercial world as well as these kinds of collaborative volunteer projects.
By the way, the best sites I've seen so far for monitoring stats are BOINCstats and Free-DC. They both seem to have a decent set of graphs and data to analyze my progress. But the other stats sites have some cool stuff as well (Stats 'N Stones, Synergy, The Knights, all Project Stats, Combined Statistics). If anyone else has any favorite projects let me know. I probably try branching out in the next few weeks.
UPDATE: I decided to join Einstein@Home as well, but I'm still open to other project suggestions.