For something quick (and not necessarily dirty) you can use XFig — TeX symbols are allowed, and there's quite a lot you can do (it's quite impressive how powerful this 'oldie' can be ;-).

For something more elaborate, i'd say PGF and TikZ — this is a very powerful tool, and you can virtually do whatever you want with it.

For some sort of "middle ground" approach, you can maybe try Xy-pic — this is not as old as XFig and not as new as PGF/TikZ; and used to be the standard way to go for graphs. ;-)

Hope this helps.

PS: I'm a new user, so can't post links yet… so, i used bold instead: just search for the terms in bold and you should be all set. ;-)

Edit: to include the links (now that i can post link ;-).

For something quick (and not necessarily dirty) you can use XFig — TeX symbols are allowed, and there's quite a lot you can do (it's quite impressive how powerful this 'oldie' can be ;-).

For something more elaborate, i'd say PGF and TikZ — this is a very powerful tool, and you can virtually do whatever you want with it.

For some sort of "middle ground" approach, you can maybe try Xy-pic — this is not as old as XFig and not as new as PGF/TikZ; and used to be the standard way to go for graphs. ;-)

Hope this helps.

PS: I'm a new user, so can't post links yet… so, i used bold instead: just search for the terms in bold and you should be all set. ;-)