So let's assume that Harry is 25 come Storm Front. That would have Storm Front and Fool Moon take place in 2002 (He'd turn 25 in 2001, and Storm Front takes place in Spring.) Grave Peril would be 2003, Summer Knight 2004, Death Masks 05, Blood Rites 06, Dead Beat 07, Grave Peril either 08 or 07, White Night 08, Small Favor, 09, Turn Coat, 11, Changes 2012.
If He was born in 74, than it would be
2000: SF and FM
2001: GP
2002: SK
2003: DM (Mayoral election year in RL, which is also occurring in the book).
2004: BR
2005: DB
2006: PG
2007: WK
2008: SF
2010: TC
2011: C
2012: GS AND CD
If Harry was born in 75
2001: SF and FM
2002: GP
2003: SK
2004: DM
2005: BR
2006: DB
2007: PG
2008: WK
2009: SF
2011: TC
2012: C
2013: GS and CD
1976
2002: SF and FM
2003: GP
2004: SK
2005: DM
2006: BR
2007: DB
2008: PG
2009: WK
2010: SF
2012: TC
2013: C
2014: GS and CD
All in All I think the 1974 birth is the most plausible; it even adds nice parallels to the real world
ex
1.) Mayoral elections line up and the Terrorist paranoia that Nick presumably planned to exploit in the aftermath of the deadly plague. Also
2.) Beginning of the War on Terror corresponds with the beginning of the Vampire War; End of Iraq War and death of bin laden corresponds with the end of the Vampire War