As of 2013, I've visited 7 current stadiums:

Seattle (Safeco Field)
San Francisco (AT&T Park)
Oakland (when venue was called Oakland-Alameda County Stadium)
Denver (Coors Field)
Chicago (Wrigley Field)
Toronto (when venue was called the SkyDome)

New York (CitiField)

In addition,

Chicago (Comiskey Park)

Milwaukee (County Stadium)

Cincinnati (Riverfront Stadium)

New York (Shea Stadium and [Old] Yankee Stadium)

And finally,

Montreal (Olympic Stadium)

I hope to travel to see the other 23 MLB stadiums in my lifetime. However, unlike others, I'm taking the trips one stadium and one season at a time.

Thanks for reading this post.