Xperl is pretty good. But I do hate the mem hog it is..

I use pitbull, dominos, kg panels for looks, Grid, arkinventory (bags). Plus a ton other addons. Major patches will break a few things but hardly ever has it broke my buttons, ui frames, or any other major addon. The small stuff will break like autobar. But is normally fixed in a day or 2.

I suggest go to www.wowinterface.com and search their compolations and see if you see a ui you like. Tweek it and go from there.

NUI is a very well known UI. And the man who creates it and updates. Keeps it up to date. It is how he makes his living. So if your worried about a ui breaking on patches this is the one to get. His ui is neat. And works pretty well for boxing. Getting used to the button setup is a little different (for me) but it does work great.

Insomniac's I haven't used in some time. Its a little messy when you download it. But again its a guy who runs a major guild and kept it up to date for a very long time. You just have to weed out the bloated stuff you don't want.

Spartian ui is another one that is a well known ui. Works great. Easy to use. Download log in and your set up. The only thing I ever had to adjust was my chat box. Everything else is already done. Does not have a bag addon.