Here's my take. I lived in Raleigh, worked in Durham back in 2007/2008 (so take it for what it's worth).
I moved to RDU single and was told by the younger folks I interviewed with that Raleigh was the best option to live for a young professional. Chapel Hill was very much a college town, more so than Raleigh. Durham was not where you wanted to live. So I chose Raleigh.
Re: Durham - It's come a LONG way over the last 10 years. Lots of good dining options and a safer place to live than when I was out that way. The downtown was not where you'd want to be after dark back in '08 but has much more nightlife and less crime now. If I was to move back I'd give Durham a hard look.
Raleigh - While I liked living there okay, coming from Austin it left a lot to be desired as a fairly young, single person. I lived inside the loop and got the feel that Raleigh hangs out with Raleigh. Lots of kids grew up there, went away for college and came home to all hang out together, marry one another and stay close knit. Nothing against that except being an outsider, I definitely felt that way. As you get outside the loop, my guess is that this would be less so.
As others have mentioned with Cary, Apex, others, there are a lot of very large bedroom communities that are great for raising a family. You're not there yet so may not be your ideal situation unless you just really want a good size house, quiet neighborhood.
Chapel Hill - Very much a college town (a beautiful one). But Carrboro is essentially connected to CH and it's the closest thing to an Austin/78704 vibe. This would also get a hard look from me if I were to move back.
My dining options may mostly be outdated but I concur with the lack of passable Tex-Mex. I'll 2nd Poole's as a great place in downtown Raleigh. Nicer, trendier than Threadgill's.
Location of the area is awesome as it's an easy drive to the beach and the mountains and a fairly easy drive to a lot of other good long weekend trips in the SE.