This is a tough situation for me. I'm actually not that much of a fan of the original movie except in retrospect as it relates to the SG-1 canon (and SG-1 still takes precedence to me as far as retconning goes).
But from what I've heard of the potential SG-1/SGA movies, I'm not too confident in how they would have turned out either. Despite a shaky start, Universe got really good near the end, so I would have liked to see that continue, but that has passed now.
And I'm not really sure there's a lot of potential for a new series that follows the canon to capture a large enough audience to continue. The technology and mythology developed so far that I don't know what else they could do with it.
So in that regard, I'm not entirely against a reboot movie at this point, however my concern is Emmerich's disregard for the series, and if it's a trilogy of movies, I suspect it could have too conclusive an ending to allow any kind of rebooted series, and if it did, it may not be too similar to the series we know and love.
Stargate is my favourite scifi franchise, but I just really don't know how I'd like it to progress from here.
On one hand, having it revived and popular in any form can be a good thing. The new Transformers movies weren't great, but they gave us Transformers: Prime, perhaps the best of all the series, and a renewed interest in the franchise.
On the other hand, it's not the same Stargate I'm interested in, and could create the same divide between new and old fans that the new Trek movies have, and how the franchise progresses from there is anyone's guess at the moment.