Whoa, Stuart, nice job man! You're improving much faster than I imagined you would. Anyhow, the first Naru banner was really well done. You chose a nice background color but Naru was a bit fuzzy though, and the text a bit too dark. While some would think the boarder a bit too thick, I didn't find it all that distracting. In fact I hardly noticed there was a border at all. I guess my eyes were really attracted to that pic of Naru. :D
I'm not really keen on that second Naru though. There is too much empty space used for the text, I think.
Despite being rather plain, the Majin Buu animation really fits together nicely. Overall, a well rounded effort.
The next Love Hina based banner is all over the place, and in a bad way. The cutout of Naru is nicely done and the drop shadow really makes her stand out, but the background is too much of a jumble. Perhaps it would work better for me if the whole background where done with that same pattern...
Finally, that Subaru banner is jaw dropping! Excellent use of shapes and that thin border is perfect. However, the left picture of Subaru is a little too fuzzy. I suggest making a selection of just her, feathering it a bit, and then apply the sharpen filter, or unsharpen mask to seperate her from the background. Fantastic work, I don't think that banner even needs text.