of volunteering and motivations

Had an interesting thought last night as i drove home from the orientation session for 'Habitat for Humanity'; i wondered if i could quiet the pace and noise of all that's going on and look into my heart.  And, doing that, i wondered: what is my reasoning behind all this volunteering? 
I do believe it comes out of a transformed heart that wants to serve God by helping those less fortunate around me, however i could also see this selfish desire there that was solely about serving myself and getting volunteer work that will "look good on a resume" and nothing more.
How wicked is my heart still?  God forgive me and may He use, even these mixed desires, for His glory and the benefit of those i serve in these volunteer efforts.

You can check out what H4H is doing currently at this address: http://www.vancouverhabitat.bc.ca/