Delixe: Well it wasn't strictly a Deus Ex ending it was an (hopefully my spelling is right) Ontological Paradox. I thought it was rather cleverly done overall and a vast improvement over previous RTD finale's that tended to pound great big plot holes with a sledgehammer. It was also nice to have a happy ending for a change.
No idea what happened to the Blinovitch Limitation Effect though which was established back in Day of the Daleks. I guess with reality collapsing all the laws of time were thrown out the window.
<SPOILERS AHEAD! PROCEED WITH CAUTION>
The D-E-M bits for me were the magical Pandorica, the light of which was necessary for everything to conclude positively (Amy and the Doc are shot and the Pandorica heals them). Also, it's this "light" that has the required capacity to recreate the universe.
The ontological paradox (use of the vortex manipulator wrist time-travel device) is handwaved by the universe collapsing.
The Blinovitch effect is noted when the doctor touches the two sonic screwdrivers (there's a big spark), but nothing happens when he touches his dying self.
</SPOILERS>
If you ignore those sorts of things (kinda have to, especially in modern doctor who), it was a very good episode.