I too, got this to happen to me on friday (before friday's new build and saturday's) and have yet to try it again today.

However I go no debug file or dump file, no error message or no crash report at all.  It simply CTD when I hit end turn and that was it. 

Win XP

2 gig ram

Nvidia 9500

Intel Dual core

I'll post an update after I play it today to see if it continues this behavior with the new builds.

Yes, still happening to me after two updates.  This appears to be a windows xp problem? 

I played the game at home on win 7 x64 with 0 problems.

I have this also but with Vista 64 bit ultimate (oh mine doesn't CTD, but instead just hangs not responsive, I need to kill it through task manager).  The turn button stays greyed out for at least 3 minutes.

I suspect it has something to do with the autosave feature or a city upgrading to the next size, but being too close to the ocean or other blocking items on the map.  I need to do more testing with this to lock down the problem.  One issue with tracking down the problem is that if it happens it seems to bork my last save into not loading, so I have to go back further.

I also don't think saves are tracking all the items right, I need to write down a bunch of stuff associated with a save and then track what happens after reloading it.  Convolved in this is the autosave feature which seems to be doing something bad.

I just got into the beta, so I am learning the game to start with so I can tell what is going on easier.  Got one game over 200 turns with 4 cities, but it is getting buggy and freezing/crashing much more.  I might try deleting things to see what is causing it.

hmm. i'll have to turn off autosave and try this.  the sad thing is, with it ctd, autosave is the only way to make sure you don't lose progress...