Rave, don't you think that "Blogs" and "Journals" are rather redundant...
You made really great banners, and if I was allowed to vote for them (Since I entered, I will not be voting), I would vote for yours, I have to say the filesize is an issue.
Keep in mind that while making the image transparent is a good idea, the PNG fileformat is a problem since it is a Lossy format (Meaning no image quality is lost during compression). Those three banners are over 300kb each, the current banners that are up right now are all under 100kb.
This is key to web design, especially on a traffic heavy site like ours, where a balance of Quality and speed of loading must be maintained (Hence the 200kb sig filesize rule).
My suggestion is to save them as JPGs (since they will most likely be changed to that if they are chosen anyways)