They are all very Web 2.0-ey, which is fine but it's hard not to make something look nice when you pull in a lot of pretty visual elements (as long as you don't overdo it.) I felt as though the OP was more concerned with layout and how to present information and use columns and so on, especially since the sample he posted looked pretty enough but was just one long column of text in sections.
Also the only corporate looking tutorial "Design a Professional Business Web Layout
Use drop-shadows and gradients to create a stylish 3-D look." (about a third of the way down) looks terrible! Unbalanced, unfinished and instead of professional just looks deliberately boring and stereotyped.
Having said all that, they are a nice set of tutorials, thanks!