Here's a few effects shots that have bothered me:
-The Executer bridge tower as Han and Company wait for the code to clear looks too modely
http://picasaweb.google.com/lh/photo/bGlIfESK9bY_mP2MXkGH-g?feat=directlink The Death Star could use some work here
http://picasaweb.google.com/lh/photo/ssziDf6AAP-G6Y0k2LJxAA?feat=directlink
http://picasaweb.google.com/lh/photo/q5S9WlqNihZparb5DynE7A?feat=directlink The Death Star looks almost red in some points
-This scoutrooper who's calling for help after knocking over Han is losing his mask, you can even see his face
http://picasaweb.google.com/lh/photo/cckaUXkNEjbDGnudOsul1g?feat=directlink
-There's a shimmering effect around the speederbikes as Han watches Luke and Leia take chase (couldn't get it in a screenshot). Might be a brightness issue.
-In the 2004 DVD the laserbolts from the speederbikes are now a very pretty yellow ;)
-The speederbike chase needs some mattelines removed in some shots
http://picasaweb.google.com/lh/photo/SnYuhakgZAyGeJoPnT327A?feat=directlink
-During the chase a laserbolt hits a tree but nothing happens.
http://picasaweb.google.com/lh/photo/Ci4XHJ0yAyfiXPQebOYs4w?feat=directlink
-An explosion from a speederbike that got hit can be seen through the tree that blocks it from the camera momentarily
http://picasaweb.google.com/lh/photo/v_qEumw4-X4tfPFlhTNFCQ?feat=directlink
And it even separates from the speederbike after the tree passes! http://picasaweb.google.com/lh/photo/weP4lIQgez5w8E9uNcGz-A?feat=directlink
EDIT: Removed an "error" that wasn't really an error