I wouldn't fault anyone for bumping an old but still semi-relevant thread, but if people wanted to screenshot their ui's they should probably post it in this newer thread.
While UI's are basically up to personal preference, I do want to say that I recommend the excellent
Razc~ UI in addition to the profit ui that most people seem to use. Razc has some advanced features not seen in other UI's plus is visually streamlined, so unnecessary windows aren't featured. (For example, it consolidates group window and raid window when in raid).
As far as spell setups and casting order of my hotbars, I'm a bit lazy to take a screenshot and post it, but I use a spiral-type pattern with Hostage, TM and Spell Curse all in the middle. The other most frequently used spells are clustered near it and mapped on my right side keyboard. Most other people use a straight-line casting order, which is easier to learn at first, and use the number keys.