I'll always have a soft spot for Assembly Hall, but one of the best college basketball atmospheres I've experienced was at Allen Fieldhouse. I've been to two different games there The first one was when they played NC State. That was great, but last December I saw Kansas play UConn and that was on a whole other level. It was hands down the loudest basketball game I've ever been in and everyone seemed into the game right from the opening tip. They also do a good job with all the history in the concourse and surrounding areas. 

Cameron Indoor Stadium was great, but if I had to rank them, Allen Fieldhouse is tops for me. I also loved going to OSU's St Johns Arena growing up. Value City Arena isn't the greatest venue. I kind of wish they would have retrofitted St. Johns. It's still there, but rarely used. 

Just from pure visual architecture, and overall enjoyment and experience... 

1.  PNC Park

2.  AT&T, or whatever they call SF Giants

3.  Lucas Oil

4.  Wrigley

5.  Fenway

6.  Coors Field

7.  IU Memorial Stadium (after all recent renovations)

8.  IU Assembly Hall

9.  Dodgers Stadium

10.  Lumens Field, or whatever they call Seahawks stadium

I'd have to make a special category for HS basketball gyms, as the good ones of those are right up there with overall enjoyment.  Cool baseball stadiums just hit different.  But the architects and planners for Lucas Oil did an absolutely incredible job.