I pretty much work the same as MOP, with a bit of pelt mapping thrown in....only plugin/script I use is the one Low Odour wrote for seam elimination... http://boards.polycount.net/showflat.php...true#Post175645
If you don't want to use Chuggnuts tools, try Fat Assasins' scripts. The most useful ones for me have been horizontal and vertical align, bind them to a short cut key and you'll have straight edges instantly.
I don't use any plugins, just but do have a little custom toolbar with scripts for quick UV alignment. For organic stuff, Pelt mapping and Relax are your friend. Since I also do lots of environmental work, just the simple UV Planar and Cylindrical, as well as Flatten and Normal Box mapping usually get the job done.