Here is a general replacement UI that you may wish to consider:

TUKUI - HOMEPAGE

DOWNLOAD (The actual addon)

DOWNLOAD (The config tool for the addon)

I'm currently just about to give it a try as it looks quite slick and has had good reviews.
As far as I'm aware this addon is not available via Curse.com so you'd have to update it manually in the future.


WARNING!
Before changing any UI majorly I suggest backing up the following folders in your WoW directory: Addons, WTF this can be done by simply compiling them in a zip file.

I've been using Tukui for quite a while now, and more recently moved to Elv22's edit. Good addon, and bugs are usually fixed quite quickly.

This is a useful addon to install as well.

I remember having a look at this.

I Iiked the idea, but I don't think they supported Windowed mode or low resolutions, so it was a no-go for me.

Windowed mode seems fine. Define "low" resolutions?

Under 320x240, which is what my alts were running on at the time =P