It's hard for me to be too excited about this anniversary. Don't get me wrong - I love TESB, and depending on what mood you catch me in, I might even say it's my favorite of the SW films. Though not by very much.
But too often I see it used as a bludgeon against each SW film that came after it. Seeming "flaws" that the four subsequent four films get raked over the coals for (dialogue, acting style, etc.) TESB for some reason gets a pass on. That irks the shit out of me. TESB wasn't universally loved when it came out either, but the media now acts like it was (in using it as the aforementioned bludgeon). That also bothers me. I'm actually a little bit uneasy about Celebration V because of the overwhelming focus on TESB - which on its own I'd be fine with, if I didn't suspect a lot of ROTJ and particularly PT backhanding to come along with it. Hopefully The Clone Wars and GL's presence (woohoo!) at Celebration will provide a good counterbalance.
That said: it's a great movie, if a little stylistically dry. If it weren't for TESB, the saga as I know and love it wouldn't have happened. As
lazypadawan basically remarked in her own TESB post, it's what shifted the central focus of the saga to family drama, and the tragedy of Darth Vader. I love ROTJ and the PT and those films wouldn't have near the resonance for me that they do if not for the direction TESB took the saga. I love the saga as a whole, and TESB is an absolutely integral part of it.
Happy birthday, TESB!