Sure. Now, I have to ask a question
.
Do you prefer simple or do you like to fidget with you UI, tweaking it constantly?
If you just want some pretty simple art (bottom art, for the entire bottom section of screen), I'd recommend SunnArt. It's simple to use, has a decent selection of art that you can get a hold of and easily implement. Has a built in viewport.
If you like to sit and make an entire theme of that art, bottom panel, other frames (Recount, Omen, pretty much anything with an identifiable frame), then I'd recommend KGPanels. It's not quite as simple as SA, but is much more customizable. If you go this route and want a viewport (makes the game world show above the bottom art, instead of behind it), you'll need a separate addon such as NefPort (uses slash commands to size your viewport). There are a lot of art packs people have uploaded here to the site that integrates well with KGpanels, or you can make your own (there are tutorials on the site also, but requires a good understanding of the search feature on this site).
Also, what unit frames are you using (looks like xperl or PitBull)? Are you pretty much hooked on them? If not, I'd recommend looking at STuf, they are just awesome for making 'the pretteh'.
AND... if you don't want to put a huge effort in, and want to go with a preset UI that is pre built... I'd recommend ANYTHING that Elloria has made. Also, you could get some good tips from just looking at her stuff (code, scripts, etc..).
Hope this helps.