I always put high value on closers in my leagues, and for some reason everyone likes to mock me. I won last year and I am running away with the league again this year. We have a few people in our league who completely punt the save category and load up on starters to inflate the total wins, inning and K's.
I have 4 closers right now - Lidge, Hoffman, BJ Ryan and Huston Street. In a given week, they usually give me the equivalent of about 1 full game (9 innings). SO I always get 4 - 5 saves minimum, which is almost always enough to win that category. And these guys have high K ratio and give up few runs. SO it's like getting a complete game, 10 strikeout game from a starter.
Botto line - don't reach for closers, but get them while you can. Last year I drafted Rivera and during the season picked up Lidge and Nathan just before the got the closer jobs and they helped lead me to victory. This year I drafted BJ Ryan late and got Street off waivers. And I am comfortably in first place.