People decry the overuse of CGI, but watching some of the behind the scenes stuff on the DVDs there's a lot of places I thought were beautiful physical sets but turned out to be completely or at least partially CGI. Either way, there's just a lot of beautiful set pieces that show just how big the galaxy these people live in really is.
As for scenes, there's a ton of set pieces in Ep 1 that are really great scenes, they just don't quite hang together that well and are marred by some really bad acting by both major and minor actors. The 4-way battle at the end seems like overkill at first, but there's a lot to be shown and it does it fairly well. (Like the Ewok battle in ROTJ though, it would benefit from seeing more of the better Gungan warriors actually fighting and holding their own. It's pretty clear they weren't immediately slaughtered and were actually taking out some of the battle droids).
Ep 2 is similar, a lot of good set pieces, that don't always flow quite right into one another. The chase over Coruscant is great though, as is Detective-Inspector Obi-Wan, and again the final battle is damn good.
Ep 3 is just all kinds of good, though I really would have loved to have seen the birth of the Rebellion scene in the movie, and maybe more post-suit Vader (and more pre-suit Vader for that matter). There was also a lot of the tie-ins to the OT in ROTS that I think a lot of fans were looking for in the first two also, though personally I'm on the fence about. I love all the unique stuff that the PT gave us, but I do appreciate all the OT nods too.
Something else that I've really started to think about seriously in the past few years is that 1 and 2 both could use another good pass through the editing bay to tweak the flow of a lot of the scenes. Add some character building scenes, and maybe trim some others for pacing.
And I've said for years the events of Ep 1 should have been the first act or the first half of Ep 1, with Ep 2 being at least one or two major battles of the Clone Wars, showing us how Anakin and ObiWan became the friends we're supposed to believe they are at the beginning of Ep 3.