The
Widescreen mod does a decent job with BG2, centering things like cinematics, the Inventory, Character, Journal and Map screens and tiling the textures on the left, right and bottom bars in a way that isn't too obvious or distracting. So I'd say an additional UI mod isn't really necessary.
BG1 is another story though. The Widescreen mod works, but no effort is made to "pretty" up the GUI -- Inventory, etc. appear in the top left of your screen, and instead of tiling the bar textures, there are just black bars. The reason for this is that it's fairly common for people to use mods like BGTutu or BGT to bring BG1 to the BG2 engine, which means the GUI is also replaced with that of BG2, resulting in all the above-mentioned "prettying up" when used with the Widescreen mod.