I thought TPM was great. It had the "feel" of ANH, and was just a fun movie all-around. Maul was awesome, and the 3-way lightsaber duel was cool.
AOTC was okay. The Jango/Obi-Wan fight was awesome, as was the last 45-60 minutes of it. It's just that the first parts of it, save for the Speeder chase and the Jango/Obi-Wan fight, were so utterly boring.
ROTS was fantastic. It had everything. Lots of lightsaber duels, we got to see the Galactic Empire in it's early days, space battles, ground battles, the Jedi Purge, etc. It had lots of things that tied in to the OT, like Tarkin and the Imperial Officers, a new alphabet ship (V-Wing), Palpatine's deformed face, Vader in the suit, etc. But most of all, it felt like Star Wars.