First off don't assume because I'm from Massachusetts that I love Fenway, in fact it is my least favorite. Fenway is an uncomfortable, overpriced dump. Since it's slow at work today I'll rank them all for you:
1 PNC Park Pittsburgh
2 Citizen's bank Park Philly
3 Wrigley Field Chicago
4 Dodger Stadium LA
5 Camden Yard Baltimore
6 Petco Park San Diego
7 Comerica Park Detroit
8 Safeco Field Seattle
9 At&T Park SF
10 Progressive Field Cleveland
11 Miller Park Milwaukee
12 Ballpark At Arlington TX
13 Minute Maid Park Houston
14 Great American Ballpark Cincinnati
15 Angel Stadium Anaheim
16 Citi Field Queens, NY Mets
17 Chase Field Phoenix
18 Rogers Center Toronto
19 US Cellular Field Chicago White Sox
20 Oakland Coliseum Oakland
21 (Old) Yankee Stadium Bronx, NY (Gone)
22 Tropicana Field St Petersburg, FL
23 Jack Murphy Stadium San Diego (Closed)
24 Shea Stadium Queens NY (Gone)
25 Tiger Stadium Detroit (Gone)
26 Veterans Stadium Philadelphia (Gone)
27 Cinergy Field Cincinnati (Gone)
28 RFK Stadium Washington DC (Closed)
29 Olympic Stadium Montreal (Team moved)
30 Metrodome Minneapolis (Closed)
31 Sun Life Stadium Miami
32 Fenway Park Boston (Should be demolished)
To be honest 10-17 are pretty much a toss up as are 26-30.
Anyone who lives in PA should consider themselves lucky that they have the 2 best ballparks in the country.