Single CPU vs. Dual

I recently built a dual cpu system. It was a pain to get working and cost a little more to build but now that it is done I find it better than any other system I have ever used. I'm wondering what others thoughts are on the subject of single vs. dual.

I think my favorite quote I have ever heard on this debate is that single cpu systems lack the "creamy smoothness" of a dual, meaning that you can really have your system doing two things at the same time and have it feel like you are only doing one. Anyway my configuration is thus:
CPUs: 2 AMD Athlon mps 1800+, I've overclocked them to about the 2100+ level.
MB: Asus A7m266d
Memory: Samsung Registered ECC PC2100 DDR 1 Gig. (This was one of the painful things because my MB won't recognize non registered, though it says it should)
Video: Abit Silura GF4 TI 4200

So what do you think? Also can anybody recommend a good free benchmarking tool? I wonder how it compares.