Filling in the background

what other tool beside the magnetic lasso tool can I use tooutline a subject in order to darken the background withoutaffecting the subject itself? More specificly, is there a way todraw a line (without using the marquee tool) at different angles otherthan perfectly horizontal or vertical in order to outline a subjectthat has straight lines (such as furniture) so I can darken thebackground and not have a jagged looking edge on the subjectitself?