I think I know the sound your talking about. I consider it a normal 4 cylinder engine noise. Comming from a Toyota Tercel, then a '03 Corolla to my '04 Accord, it's been a steady improvement. YOu want to hear valve noise... listen to my Kawasaki 900cc Inline 4 on my motorcycle. The cam chain tensionser and the stiff valves springs which allow a 12,000 RPM redline make a heck of a racket.

Suprisingly I though the new '06 Civic was a little quieter, but it also has a smaller SOHC engine which has a slightly less mechanicals.