[Tallguy]

I think she still has the longest flight deck, but her displacement (which is what most size comparisons take into account) is smaller than the Nimitz's.

[quietolong]

It is longer:

Navy fact File
http://www.navy.mil/navydata/fact_display.asp?cid=4200&tid=200&ct=4

General Characteristics, Enterprise Class
Displacement: 89,600 tons
Length: 1,101 feet 2 inches

General Characteristics, Nimitz Class
Approximately 97,000 tons
Length: 1,092 feet

USS Enterprise CVN-65
http://www.enterprise.navy.mil/