I definitively agree. This is the main reason why I use jEdit. Their block selections are superb. jEdit even supports 0-width block selection, and typing inserts values on all lines.
For example
int a;
int b;
int c;
can be easily turned into:
int myVariable_a;
int myVariable_b;
int myVariable_c;
I personally think this would give SharpDevelop an edge over VS Express editor.